Patent Description:
The present invention relates to a dynamic balancer. In particular, the present invention is directed to a dynamic balancer which uses a frameless motor drive in determining a balance condition of a tire rotated by the balancer.

Manufactured tires generally undergo certain testing before being made available for sale to the public. One such test includes measuring the balance of a tire by rotating the tire at a high speed. The machines used for measuring the balance of a tire must secure the tire in position, inflate the tire, and then rotate the tire at a high speed while detecting forces during the tire's rotation. Devices according to the prior art are disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

Prior art devices typically utilize load cells that detect forces in an axial relation to the tire's rotation. Although effective in its stated purpose, it is believed that more accurate determinations of a balance condition can be obtained. For example, a common problem with prior art dynamic balancers results from the mechanism utilized to rotate the tire to determine a balance condition. Most all balancers employ a side-mounted motor that rotates a belt coupled to a spindle assembly that rotates the tire. A side-mounted drive motor, although effective, introduces radial forces to the spindle assembly, which must then be compensated for so as to not adversely affect sensors that determine the balance condition of the tire. This compensation may be done by either application of counterbalancing forces, use of sensors to determine added forces and computer processing to adjust the measured forces or a combination of both. Some dynamic balancers avoid the use of side mounted motors by employing a drive motor housing and an armature. However, such a configuration still employs opposed suspension springs, which become unbalanced after minimal use and introduce forces into the spindle assembly which must be compensated for, either of which result in distortions in the load cell measurement.

Another drawback of prior art dynamic balancers is the way in which the tire is secured to the machine prior to rotation. One prior art chuck locking mechanism employs ball bearings between an outer sleeve and an inner sleeve to hold the tire in place. Unfortunately, the bearings are easily misaligned and the sleeves do not engage with one another as they should.

Accordingly, there is a need in the art for an improved tire balancer that detects forces in a horizontal plane in relation to the tire's rotation. And there is a need to collect and process the forces detected in a meaningful way to properly identify a location and amount of a tire's out of balance condition.

In light of the foregoing, it is a first aspect of the present invention to provide a dynamic balancer according to appended claim <NUM>.

These and other features and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings wherein:.

Referring now to the drawings, and specifically to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, it can be seen that a dynamic balancer is designated generally by the numeral <NUM>. Reference should be made to these specific drawings when reading any part of the specification. Where appropriate, specific reference may be made to the relevant drawings, but it will be appreciated that any of the drawings may show the item being described. As is well understood in the art, a dynamic balancer tests toroidal bodies, such as pneumatic tires. Generally, the balancer <NUM> includes a floor-supported frame <NUM> (partially shown) with appropriate structural features such as legs and cross members which carry the balancer. Skilled artisans will appreciate that the frame may be bolted or otherwise secured to a floor so as to minimize exposure to extraneous forces.

An outer housing <NUM> may be carried by the frame <NUM> and supports the major components of the dynamic balancer. Interposed between the frame <NUM> and outer housing <NUM> may be at least one load cell <NUM>. In the present embodiment, four load cells <NUM> may be spaced -- in substantially equal <NUM>° increments or as otherwise appropriate -- around the outer housing and are employed to detect and collect force measurement data during rotation of the tire by the balancer as will be described in detail as the description proceeds. Configuration and placement of the load cells with respect to the frame may be as described and shown in <CIT>. In the present embodiment, the operational interface of the load cell(s) between the balancer <NUM> and the frame <NUM> is the only intentional interface between the two so as to substantially eliminate the application of any extraneous forces to the balancer during operation. As a result, a balance condition of the tire may be obtained with minimal interfering external forces incorporated into the balance measurement by the load cells.

The major components of the balancer <NUM> may include a locking member <NUM> which is associated with and positions one side of the tire (T) and, in particular, a tire bead, wherein <FIG> shows the locking member <NUM> is received in a chucking assembly designated generally by the numeral <NUM>. The chucking assembly grips the locking member and positions and captures an opposite bead of the tire. And, the chucking assembly <NUM> may be received in a spindle assembly <NUM> which rotates the chucking assembly and the tire which is mounted between the locking member and the chucking assembly. The spindle assembly <NUM> may be rotated by a frameless motor assembly <NUM> wherein the rotational position of the tire being rotated is detected and monitored by an encoder assembly <NUM> which is coupled to the frameless motor assembly <NUM>. A spring-biased return cylinder <NUM> is associated with the frameless motor assembly and, as will be discussed in detail, assists in releasing and capturing the locking member <NUM> in conjunction with the chucking assembly <NUM>.

As best seen in <FIG>, the locking member <NUM> includes a locking shaft <NUM> which provides an outward taper <NUM> at one end. Skilled artisans will appreciate that a dry brake air system (to be described) may be coupled to the taper <NUM> and/or adjacent portion of the shaft <NUM> for the purpose of moving the locking member into and out of the chucking assembly <NUM> and inflating/deflating the tire. The locking shaft moves vertically into and out of the chucking assembly <NUM> in a manner that will be described as the description proceeds. Extending axially into the shaft at the outward taper end is an air supply bore <NUM>. Extending through the locking shaft <NUM> is a cross bore <NUM> which intersects with the air supply bore <NUM> and is contiguous therewith. At an end opposite the outward taper <NUM> is a distal end <NUM>.

In some embodiments, the locking shaft <NUM> may have a non-circular cross-section as best seen in <FIG>, <FIG>, and <FIG>. Such a feature facilitates the engagement and locking of the shaft with the chucking assembly which receives the shaft, both of which are subsequently rotated by the spindle assembly during a balancing operation. In such an embodiment, care must be taken to properly angularly align the chucking assembly to receive the locking shaft, and this can be easily done by coordination between the encoder assembly <NUM> and the motor assembly <NUM> as will be discussed. In any event, the locking shaft in the present embodiment provides a substantially square cross-section, wherein the shaft <NUM> provides multiple locking sides <NUM> and wherein each locking side is provided with a corresponding alphabetic suffix A-D. Each locking side 63A-D provides a plurality of shaft teeth 64A-D wherein a gap 66A-D is provided between each tooth. As a result, the locking sides 63A-D provide shaft teeth <NUM> that extend from about a mid-point of the shaft <NUM> to the distal end <NUM> of the shaft opposite the outward taper <NUM>. And the teeth <NUM> are provided on linear surfaces that effectively form a square cross section of the locking shaft. As such, in the present embodiment, the locking shaft provides four sides that facilitate engagement with the chucking assembly <NUM> as will be described.

A shaft collar <NUM>, as best seen in <FIG>, <FIG>, and <FIG>, may extend radially from the shaft <NUM> at a position between the cross bore <NUM> and the outward taper <NUM>. The shaft collar <NUM> may be attached with fasteners to a shaft flange <NUM> which may be attached with fasteners to an upper rim <NUM> which rotates when the locking shaft is rotated. An outer circular surface of the upper rim <NUM> may provide for a plurality of diametrically inward steps <NUM> to accommodate various tire bead diameters.

As is generally apparent from <FIG>, <FIG> and <FIG>, the chucking assembly <NUM> receives and holds a tire by virtue of engagement with the locking member <NUM>. When the locking member <NUM> and chucking assembly <NUM> secure the tire therebetween, they are collectively secured within the spindle assembly <NUM>. As will be discussed at the appropriate time, air is transferred through the air supply bore and the cross bore <NUM> to inflate the tire, whereupon the spindle assembly <NUM> rotates the captured tire to determine a balance condition and other characteristics of the tire.

Referring now to <FIG>, it can be seen that a dry brake air system is designated generally by the numeral <NUM> and is operatively coupled to the dynamic balancer <NUM>. The balancer <NUM> accommodates connection to the air system <NUM> by incorporating a coupling mate <NUM> which is received in the air supply bore <NUM> of the locking shaft <NUM>. As will become apparent as the detailed description proceeds, the coupling mate <NUM> is selectively coupled to the brake air system <NUM> for the purpose of directing pressurized air into and out of the air supply bore <NUM> and the cross bore <NUM> so as to inflate and deflate the tire at the appropriate times.

The air system <NUM> includes a system housing <NUM> which provides the necessary structure for holding the components of the system <NUM>. One of these components is a manifold <NUM> which provides a conduit <NUM> that receives pressurized air as will be discussed. At one end of the conduit <NUM> is an air coupling <NUM> which is selectively coupled to the coupling mate <NUM>. An exemplary coupling mate <NUM> and air coupling <NUM> may be provided by Staubli of Switzerland, wherein their SPC family of connectors provide an exemplary connection system that may be employed.

Continuing with <FIG>, an end of the manifold <NUM> may provide a sealing skirt <NUM> which partially surrounds the air coupling <NUM>. The sealing skirt <NUM> includes a sleeve <NUM> and a bushing <NUM>. The sleeve <NUM> and the bushing <NUM> allow for slidable movement of the air coupling <NUM> within the manifold <NUM> at the appropriate times. Extending from a lower end of the housing <NUM> is a shroud <NUM> which substantially surrounds the sealing skirt <NUM> to prevent debris from entering the coupling mate <NUM> or the air coupling <NUM>. Connected to and extending from the lower edge of the shroud <NUM> is an interface collar <NUM>. The collar <NUM> includes an attachment ledge <NUM> which is secured to a lower end of the shroud <NUM> by appropriate fasteners. Extending inwardly from the ledge <NUM> is a conical flange <NUM> which provides for a flange inner surface <NUM> which is sized to fit around the taper <NUM> of the locking shaft. Skilled artisans will appreciate that the flange inner surface <NUM> only comes in contact with the taper <NUM> when the locking shaft is being lifted away from the chucking assembly, as will be described in detail later. However, when the locking shaft is received in the chucking assembly, the flange inner surface is in a non-contacting spaced-apart relationship with the taper <NUM> so that there are no direct forces applied to the taper. As a result, no extraneous forces from the conical flange <NUM> are applied to the spindle assembly <NUM> during the balancing operation. In other words, the non-contacting relationship between the conical flange <NUM> and the taper <NUM> is done so that no forces are transferred between the interface of these two parts during rotation of the locking shaft.

The system <NUM> may include a linear actuator <NUM> which may be coupled to an end of the manifold <NUM> at an end opposite the sealing skirt <NUM>. Extending from the linear actuator <NUM> is an actuator rod <NUM> wherein movement of the actuator rod is controlled by a controller as will be discussed. In any event, the actuator rod <NUM> moves the manifold in an up/down or vertical direction. Downward movement of the rod <NUM> results in connection of the air coupling <NUM> to the coupling mate <NUM>. Upward movement of the actuator rod <NUM> results in a de-coupling of the air coupling <NUM> from the coupling mate <NUM>. Skilled artisans will appreciate that the coupling mate <NUM> and the air coupling <NUM> are configured such that both are sealed when they are disengaged from one another and that air may only flow between the two, in either direction, when both are securely seated or coupled with each other.

In operation, at the appropriate time, the actuator <NUM> is energized so that the actuator rod <NUM> lowers the air coupling <NUM> into engagement with the coupling mate <NUM>. Somewhat simultaneously, the locking shaft <NUM> is lowered by the conical flange and locked as will be described in detail later. Once the air coupling <NUM> is engaged with the coupling mate <NUM>, the collar <NUM> is lowered an incremental amount so that the flange inner surface <NUM> is no longer in contact with the taper <NUM>. Next, air and/or some other type of gas, which may be pressurized, is delivered through the manifold conduit <NUM> and into the supply bore <NUM> and the cross bore <NUM> so as to seat the tire beads into the respective rims and pressurize the tire to be tested. Once the inflation of the tire is complete, the air coupling <NUM> is disengaged from the coupling mate <NUM> and the tire remains pressurized by the closing of the coupling mate. The disengagement of the air coupling <NUM> from the coupling mate <NUM> does not cause the flange surface <NUM> to come in contact with the taper <NUM>.

During rotation of the locking shaft, the taper <NUM> is no longer in a contacting relationship with the flange inner surface <NUM>, although in close proximity thereto. As such, no mechanical or other forces are exerted on any rotating part of the dynamic balancer <NUM> by the air system <NUM>. Upon completion of the balancing test, the air coupling re-engages the coupling mate <NUM> so as to release the air within the tire to ambient. Next, at the appropriate time, the actuator rod <NUM> is lifted so that the flange inner surface <NUM> engages the taper surface <NUM> and lifts the locking shaft out of the chucking assembly.

Referring now to <FIG>, and <FIG>, it can be seen that the chucking assembly <NUM> includes a lower rim <NUM> which, in most embodiments, is substantially a mirror image of the upper rim <NUM>. The lower rim <NUM> provides for a plurality of diametrically inward steps <NUM> which match the steps <NUM> of the upper rim so as to match various bead diameters of various tires that may be tested by the dynamic balancer. An inner flange <NUM> may be connected by fasteners to and extend radially inwardly from the rim <NUM> and provides a shaft opening <NUM> extending therethrough to receive the locking shaft <NUM>. Secured to or formed as part of an underside of the inner flange <NUM> may be an upper retainer <NUM>. An underside of the upper retainer <NUM> provides a plurality of tee cavities 97A-D, wherein the number of cavities <NUM> corresponds to the number of shaft sides <NUM>. Each cavity <NUM> may provide a pair of opposed undercut tee ridges <NUM>. Slidably received in the tee cavities <NUM>, in ninety degree increments, or other appropriate angular increments depending on the number of shaft sides <NUM>, is a corresponding upper tee <NUM>, wherein each tee <NUM> has a suffix A-D which corresponds to the number of sides of the locking shaft <NUM> which provide the shaft teeth <NUM> A-D. Each tee <NUM> has outwardly extending side rails <NUM> that define corresponding side grooves <NUM>. And each tee has an opening <NUM> extending therethrough. And the tee ridges <NUM> of each corresponding cavity <NUM> are slidably received in the side grooves <NUM>. Accordingly, each upper tee <NUM> is linearly movable along an underside of the upper retainer. Indeed, each upper tee is radially movable with respect to the locking shaft.

Each upper tee <NUM>, as best seen in <FIG>, and <FIG>, is connected to a corresponding wedge jaw 103A-D which provides for a jaw body 104A-D connected to the upper tee <NUM> by a fastener <NUM> received in the opening <NUM>. Each jaw body <NUM> has a tee surface <NUM> at a top end thereof wherein a pair of opposed tee ridges <NUM> may extend from the sides of the tee surface <NUM>. As such, the ridges <NUM> prevent side to side movement of the upper tee <NUM> with respect to the jaw body <NUM>. The jaw body <NUM> also provides a plurality of jaw teeth 108A-D which fit into the corresponding gaps 66A-D provided by the shaft teeth 64A-D. In other words, the jaw teeth 108A-D provide for gaps <NUM> therebetween which receive the corresponding shaft teeth <NUM>. With the wedge jaws 103A-D engaged by the shaft sides 63A-D, the locking member <NUM> is secured into the chucking assembly <NUM>. On a surface opposite or angularly disposed from the jaw teeth 108A-D is a jaw incline surface 110A-D. Each incline surface <NUM> may provide an indented pocket <NUM> that is sized to receive a back-up plate <NUM>. As best seen in <FIG>, extending from lengthwise sides of the plate <NUM> are outwardly extending ledges <NUM> which with the incline surface <NUM> form a gap therebetween. Fasteners <NUM> may extend through the plate <NUM> for attachment to the jaw body <NUM>.

A wedge sleeve <NUM>, which is best seen in <FIG>, may be provided in a predetermined number of segments, and may be coupled to slidably receive adjacent wedge jaws <NUM>, so as to provide structural support thereto when the locking shaft is received in the chucking assembly and also to allow slidable movement within the spindle assembly as will be described. As seen in the drawings, two wedge sleeves, of similar shape, may be provided and received within the spindle assembly <NUM> as seen in <FIG>, wherein each wedge sleeve <NUM> may be associated with a pair of wedge jaws <NUM>. In other words, the wedge sleeve 117A may be associated with wedge jaws 103A and 103B, and the wedge sleeve 117B may be associated with wedge jaws 103C and 103D.

Referring again to <FIG>, each wedge sleeve <NUM> provides a sleeve body <NUM> which may be semi-circular in shape and sized so that both sleeve bodies <NUM> are received in the spindle assembly <NUM> in a manner that will be discussed. Each sleeve body <NUM> provides an outer semi-circular surface <NUM> on one side and an inner facing jaw surface <NUM> which is opposite the semi-circular surface <NUM>. The jaw surface <NUM> is configured so as to receive the corresponding wedge jaws, and in particular provides for two wedge jaw pockets <NUM>, wherein each pocket slidably receives a corresponding wedge jaw <NUM>. The wedge jaw pocket <NUM> includes a plate ramp <NUM> which slidably receives and bears against the back-up plate <NUM>. Extending from either or both sides of the plate ramp <NUM> is an edge ramp <NUM> which is not as deeply recessed as the plate ramp <NUM>. Each edge ramp <NUM> extends from both sides of the plate ramp <NUM> and may form a rail <NUM> received in the gap between the incline surface <NUM> and the extending ledges <NUM>, wherein the edge ramps <NUM> may slidably support and bear against the sides of the incline surface <NUM> not covered by the back-up plate <NUM>. Skilled artisans will appreciate that the angles of the ramps <NUM> and <NUM> correspond to the angles of the incline surface <NUM> and the received back-up plate <NUM>. In particular, the extending ledges <NUM> may be received in the gap between the rails <NUM> and the plate ramp <NUM> and may also bear against the plate ramp <NUM>. It will further be appreciated that as the wedge sleeves <NUM> move within the spindle assembly, in a manner that will be discussed in detail, the wedge jaws <NUM> and their respective connected upper tee <NUM>, which is connected to the top of the jaw body <NUM>, will also slidably move in relation to the upper retainer <NUM>.

As best seen in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, the spindle assembly <NUM> is coupled to the chucking assembly <NUM> at one end and to the frameless motor assembly <NUM> at an opposite end. The spindle assembly <NUM> is supported externally by the outer housing <NUM> and is rotatable therein, as will be discussed. The major components of the spindle assembly <NUM> may include a main spindle <NUM> which may be secured at one end to the upper retainer <NUM> of the lower rim <NUM> and at the other end to a drive spindle assembly <NUM> which is a rotatable component of the motor assembly <NUM>. Maintained within the main spindle <NUM> is an inner sleeve <NUM> which may be coupled at one end to the wedge sleeves <NUM>. A locking device spring <NUM> may be interposed between the inner sleeve <NUM> and a component of the motor assembly as will be discussed.

As best seen in <FIG>, the main spindle <NUM>, which may be a substantially tubular configuration, includes a main spindle body <NUM> which has an outer surface <NUM> opposite an inner surface <NUM>. Extending through the main spindle body <NUM> is a body opening <NUM> which receives at least a portion of the chucking assembly <NUM> which may or may not have the locking member <NUM> received therein. The main spindle body <NUM> provides a spindle rim <NUM> at a top end which may be connected and fixed to the upper retainer <NUM> by appropriate fasteners. The outer surface <NUM> provides for a step edge <NUM> that extends substantially perpendicularly inward to a step surface <NUM> which is of a smaller diameter than the outer surface <NUM>. In the embodiment shown, a spacer tube <NUM> may be received on the step surface <NUM> and in contact therewith. Skilled artisans will appreciate that the spacer tube <NUM> rotates with the main spindle body <NUM>. Disposed and captured between the step edge <NUM> and an end of the spacer tube <NUM> is an upper bearing <NUM> wherein an outer race of the upper bearing is positioned against and captured by an inner surface of the outer housing <NUM> and an inner race of the upper bearing is positioned against the step edge <NUM> and the step surface <NUM>. A bearing retainer <NUM> may be fastened to the outer housing <NUM> to hold the upper bearing in place and keep contaminants from entering the outer housing and spindle assembly. In a similar manner, an inner race of a lower bearing <NUM> is captured between the other end of the spacer tube <NUM> and the step surface <NUM>, and an outer race of the bearing <NUM> is positioned adjacent the inner surface of the outer housing <NUM>. The main spindle body <NUM> provides a spindle end surface <NUM> which is opposite the spindle rim <NUM> and which connects the outer surface <NUM> to the inner surface <NUM>.

Referring again to <FIG>, <FIG>, and <FIG>, rotatably and axially slidable within the main spindle body <NUM> is the inner sleeve <NUM>, which is part of the chucking assembly <NUM>. The inner sleeve includes a sleeve body <NUM> which provides for a radially outward extending outer collar <NUM> at one end and a radially inwardly extending and substantially closed shaft seat <NUM> at an opposite end. The outer collar <NUM> is secured and fastened to an end of the sleeve body <NUM> that is positioned opposite the lower rim <NUM>. Extending radially outwardly from the sleeve body <NUM> near the shaft seat <NUM> is a radial rim <NUM>. Extending from the outer collar <NUM> into the sleeve body <NUM> is a sleeve opening <NUM> which is sized so as to receive the locking member and, in particular, the locking shaft <NUM>. Extending into the shaft seat <NUM> is a shaft bore <NUM>, which may be internally threaded, and shaft seat countersink <NUM> may also extend into the shaft seat <NUM> and be concentrically aligned with the shaft bore. One end of the locking device spring <NUM> may be received around the shaft seat <NUM> wherein one edge of the spring <NUM> may be supported by a radially extending surface of the radial rim <NUM>.

The frameless motor assembly <NUM> may be coupled to the spindle assembly <NUM>, as best seen in <FIG>, <FIG>, <FIG>, and <FIG>. Specifically, the assembly <NUM> may be coupled to the main spindle <NUM> and the outer housing <NUM>. The frameless motor assembly <NUM> is generally used to rotate the upper and lower rims and the attached tire by virtue of the connections through the spindle assembly <NUM> and the chucking assembly <NUM>. The assembly <NUM> provides a motor housing <NUM> which includes a radially extending housing rim <NUM> which may be attached and fixed to a flange of the outer housing <NUM>. In some embodiments, the motor housing <NUM> may be provided with external radial cooling fins <NUM> which assist in dissipating heat generated during operation of the motor assembly. Maintained within the motor housing is a stator <NUM> which is secured to an inner surface of the motor housing <NUM> by an epoxy or other appropriate adhesive material wherein either or both of an outer surface of the stator <NUM> and the inner surface of the motor housing may be grooved or otherwise modified to facilitate a secure bonded connection between the two pieces. Additionally, the epoxy may fill into a number of transversely extending pipe plugs <NUM>. In most embodiments, the pipe plugs <NUM> may be transverse holes filed with a heat conductive epoxy that assists in transferring heat from inside the motor assembly to ambient.

Near the housing rim <NUM> and extending transversely through the housing, as best seen in <FIG>, <FIG>, <FIG>, and <FIG>, is at least one drain port <NUM> which may be oriented and inclined downwardly with respect to the rim. In some embodiments, multiple drain ports may be spaced around the housing rim in substantially equal increments. Positioned in the motor housing and underneath the spindle assembly may be an annular and frusto-conically shaped deflector shield <NUM>, wherein an outer edge of the shield is substantially aligned with the at least one drain port <NUM>. Any lubricating oil or other fluids that may pass from the spindle assembly or chucking assembly are deposited on the shield and pass through the ports so as to prevent their entry into the motor assembly. Operatively associated with the stator <NUM> is a drive spindle assembly designated generally by the numeral <NUM>.

Referring again to <FIG>, <FIG>, <FIG>, and <FIG>, the drive spindle assembly <NUM> includes a rotor <NUM> which rotates when electrical current is applied to the stator as is well known in the art. Secured to an interior and/or edge surface of the rotor <NUM> is a lower spindle <NUM>. The lower spindle <NUM> includes a lower spindle body <NUM> which has an outer surface <NUM> opposite an inner surface <NUM>. Extending through the lower spindle body <NUM> is a shaft opening <NUM> that is defined by the inner surface <NUM>. As is evident in the drawings, the rotor <NUM> is positioned immediately adjacent but not in contact with an inner surface of the stator <NUM>. The body <NUM> may also provide a radial rotor flange <NUM> which extends radially from the outer surface <NUM> wherein fasteners <NUM> may be used to connect the radial rotor flange <NUM> to an end of the rotor <NUM>. Extending axially and radially from the lower spindle body <NUM> is a spindle flange <NUM>. The spindle flange <NUM> receives fasteners <NUM> which connect the flange to the spindle end surface <NUM> of the main spindle body <NUM>, wherein the lower spindle body <NUM> and the main spindle body <NUM> together form the main spindle <NUM>. A support ring <NUM> may also be secured to the flange <NUM> by the fasteners <NUM> to support the inner race of the lower bearing <NUM>. Therefore, as the rotor <NUM> rotates, the drive spindle assembly <NUM> rotates along with the main spindle <NUM> which in turn rotates the lower rim <NUM> and the locking shaft <NUM>, when received in the chucking assembly <NUM>, which also simultaneously rotates the upper rim. The spindle flange <NUM> provides a flange surface <NUM> which supports the locking device spring <NUM> at one end, wherein the other end of the spring is supported by the radial rim <NUM> of the inner sleeve <NUM>.

A spindle shaft designated generally by the numeral <NUM> is received through the shaft opening <NUM> of the lower spindle body <NUM>, as seen in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>. As will be appreciated as the description proceeds, the lower spindle body <NUM> rotates with the spindle shaft <NUM> and is supported by at least two bearings <NUM> which are positioned at respective ends of the lower spindle body's inner surface <NUM>. And at the appropriate time, the spindle shaft <NUM> may be axially movable within the lower spindle body. As such, skilled artisans will appreciate that the spindle shaft <NUM> is used to support the rotation of the lower spindle body and the rotor <NUM>. The spindle shaft <NUM> provides for a sleeve end <NUM> with a shaft tip <NUM>, which may be externally threaded, that extends into the shaft bore <NUM> of the inner sleeve <NUM> and wherein a portion of the shaft <NUM> may extend into the countersink <NUM>. Accordingly, the spindle shaft is fixedly secured to the inner sleeve <NUM> so that axial and rotational movement of the spindle shaft results in corresponding axial and rotational movement of the inner sleeve <NUM> and the attached wedge sleeves <NUM>. And it will further be appreciated that the spindle shaft <NUM> may be axially movable within the locking device spring <NUM>, which in the embodiment shown is a coil spring, although other biasing devices may be employed.

As best seen in <FIG>, <FIG>, <FIG>, and <FIG>, an opposite end of the spindle shaft <NUM> includes a cap end <NUM> from which axially extends a cap tip <NUM> which may provide an externally threaded surface <NUM>. The threaded surface <NUM> may receive a shaft cap <NUM>. A hex nut <NUM> may be used to secure the shaft cap to the cap tip <NUM> of the spindle shaft.

An encoder assembly <NUM> is positioned between the frameless motor assembly and the spring-biased return cylinder <NUM>, as seen in <FIG>,<FIG>,<FIG>, and <FIG>. The encoder assembly <NUM> includes a mount plate <NUM> which extends from and is connected to the motor housing <NUM> wherein a plate opening <NUM> extends therethrough to allow for the spindle shaft <NUM> to pass therethrough. The mount plate <NUM> may provide at least one plate notch <NUM>. The assembly <NUM> may also include an encoder ring standoff <NUM> which provides a tubular body <NUM> wherein the spindle shaft <NUM> extends therethrough. The ring standoff <NUM> may include a spindle end <NUM> which is connected to the drive spindle assembly <NUM> and specifically to the rotor <NUM> and/or the lower spindle body <NUM>. Opposite the spindle end <NUM> is a mount end <NUM>. An encoder ring <NUM> is secured to the mount end <NUM> and, as a result, extends axially away from the mount plate <NUM>. Accordingly, rotation of the spindle assembly and specifically the rotor <NUM> results in corresponding rotation of the encoder ring standoff <NUM> and the encoder ring <NUM>. A cylindrical mount <NUM> may also be a part of the encoder assembly <NUM>. The cylindrical mount <NUM> may provide a mount body <NUM> which has an opening therethrough to accommodate the shaft <NUM>. A mount flange <NUM> radially extends from one end of the body <NUM> wherein fasteners are used to secure the mount <NUM> to the mount plate <NUM>.

A sensor mount, which is best seen in <FIG> and <FIG>, designated generally by the numeral <NUM>, is juxtaposed with the encoder ring <NUM> wherein the sensor mount holds a read head <NUM>, which is aligned with the plate notch <NUM> and which detects the rotational position of the rotor and the spindle assembly by monitoring the rotational position of the encoder ring <NUM>.

A locking bar <NUM>, which is best seen in <FIG> and <FIG>, is utilized to movably hold the position of the read head <NUM> on the mount plate <NUM> in a desired location with respect to the encoder ring <NUM>. This is accomplished by use of an adjustment mechanism <NUM> which may include an adjustment bar <NUM>, which may be slidably received in the plate notch <NUM>. An adjustment knob <NUM>, which has a shaft that may extend into the adjustment bar <NUM>, moves the adjustment bar to properly position the read head <NUM> in relation to the encoder ring <NUM>. The adjustment knob <NUM> extends through a plate <NUM> that is secured to a radial edge of the mount plate <NUM>. The locking bar <NUM> will hold the adjustment bar <NUM> in place once the position of the read head is set. Skilled artisans will appreciate that the sensor mount is removable so as to allow replacement, adjustment, and/or maintenance of the read head <NUM> without total disassembly of any other portion of the balancer <NUM>.

An appropriate position signal is generated by the read head <NUM> upon detection of encoder ring movement and transmitted to a control system (not shown) which coordinates or associates the rotational position of the tire during the rotation of the main spindle. This information along with other sensor information obtained during the rotation of the tire by the spindle assembly is utilized to determine a radial balance location of the tire under test. In other words, location of an angular displacement of rotation of either a heavy spot or light spot of the tire can be obtained with the data generated from the load cells and the encoder.

The spring-biased return cylinder <NUM>, which is best seen in <FIG> and <FIG>, may be carried by or mounted to the cylindrical mount <NUM> and surrounds an end of the spindle shaft <NUM>, but does not touch the spindle shaft. The cylinder <NUM> includes a main cylinder <NUM> which has a shaft opening <NUM> therethrough. Extending from the main cylinder <NUM> is an external radial ledge <NUM> which provides a spring surface <NUM> on one side and a ledge surface <NUM> on an opposite side. The main cylinder <NUM> also includes a cap surface <NUM> that connects an inner and an outer surface of the main cylinder and which faces the shaft cap <NUM>. Annularly surrounding the main cylinder <NUM> is an outer cylinder <NUM> which has a cylinder wall <NUM> from which extends radially inward an internal radial ledge <NUM> that in a default condition is positioned adjacent, and in some embodiments in touching contact with, the ledge surface <NUM>. Also extending radially inward from the cylinder wall <NUM> is an inward spring ledge <NUM>. And extending axially from the outer cylinder <NUM> is a mounting bracket <NUM>, which extends between the cylinder wall <NUM> and the internal radial ledge <NUM>, and which is secured by fasteners or otherwise to the mount body <NUM>. Moreover, the internal radial ledge has a ledge sealing surface <NUM> that seals around an outer surface <NUM> of the main cylinder <NUM>. Together, the main cylinder <NUM> and the outer cylinder <NUM> form an annular spring cavity <NUM> between an outer surface of the main cylinder <NUM> and an inner surface of the outer cylinder <NUM> and between the spring surface <NUM> and the inward spring ledge <NUM>. A plurality of fasteners <NUM> extend axially through the cylinder wall <NUM> and connect the mounting bracket <NUM> to the internal radial ledge <NUM> and a lower edge of the mount body <NUM>. Disposed within the annular spring cavity <NUM> is a cylinder spring <NUM> which is biased between the outer cylinder and the main cylinder and, in particular, between the spring surface <NUM> and the inner facing spring ledge <NUM>.

As best seen in <FIG>, extending through the main cylinder wall is a port <NUM> through which pressurized air may be delivered. As can be seen in <FIG>, <FIG> and <FIG>, the port delivers pressurized air between the internal radial ledge <NUM> and the adjacent ledge surface <NUM>. The internal radial ledge <NUM>, the ledge surface <NUM>, an outer surface of the main cylinder <NUM>, and an inner surface of the outer cylinder <NUM> form an annular cavity <NUM> which receives the pressurized air delivered through the port <NUM>. Delivery of air through this port and into the cavity <NUM> causes the external radial ledge <NUM> of the main cylinder to move from a default position and compress the cylinder spring <NUM>, which in turn drives the cap surface <NUM> axially away from the motor housing. The surface <NUM> engages and moves the shaft cap <NUM>, which in turn moves the spindle shaft <NUM> axially away from the motor assembly so as to move the spindle shaft to a release position. Release of the air from the cavity <NUM> allows the spring to expand and thus removes the driving force of the cap surface <NUM> away from the shaft cap <NUM>. This returns the spindle shaft to its normal default position. Skilled artisans will appreciate that the return cylinder only applies a force to the spindle shaft <NUM> and the dynamic balancer to disengage the chucking assembly <NUM> from the locking shaft <NUM> which allows removal of the tire from the balancer. The return cylinder does not apply any forces during rotation of the spindle assembly. As a result, no extraneous forces are imparted by the return cylinder to the balancer <NUM> during a tire balancing operation.

Referring now to <FIG>, it can be seen that a control system is designated generally by the numeral <NUM> and is utilized to operate the dynamic balancer <NUM>, which is shown schematically. However, reference should also be made to all the other drawings and the description above. The control system <NUM> includes a controller <NUM> which provides the necessary hardware, software, and memory to control the various components of the balancer and facilitate its operation. The controller <NUM> receives input signals and sends output signals to various components of the balancer <NUM> so as to control and coordinate their specific operation. A pressurized air supply <NUM> is coupled to the return cylinder <NUM> wherein the pressurized air is utilized to operate the chucking assembly <NUM>. The air supply <NUM> is controlled by the controller <NUM> via the control signal designated by the capital letter A.

The dry air brake mechanism <NUM> may be selectively coupled to the locking member <NUM> for the purpose of inserting the locking shaft into the chucking assembly at the appropriate time for capturing a tire and running the balancing test and withdrawing the locking member when the balancing test is complete. The mechanism <NUM> is controlled by the controller <NUM> via the control signal designated generally by the capital letter B. A pressurized air supply <NUM> is coupled to the locking member through the mechanism <NUM> for the purpose of delivering pressurized air into the tire when it is captured between the upper and lower rims. The pressurized air supply <NUM> is operatively controlled by the controller via the control signal designated generally by the capital letter C. After the balancing operation is complete, the tire is deflated and the air is exhausted through the mechanism <NUM> as described above.

A power supply <NUM> is coupled to the motor assembly <NUM> for the purpose of delivering electrical power thereto, which rotates the rotor and the spindle components at the appropriate time and speed. The controller <NUM> sends and receives a control signal to the power supply which is designated by the capital letter D.

Rotation of the rotor and spindle components is detected by the encoder assembly <NUM> and in particular by the read head <NUM>. The controller <NUM> receives the position signal generated by the read head and which is designated by the capital letter E.

At least one load cell <NUM>, and in the embodiment shown four load cells may be employed, is positioned about the outer circumference of the outer housing <NUM> wherein the load cells are positioned in an operative relationship with the frame <NUM> and communicate with the controller <NUM> via the control signal F. The load cells detect forces generated by the rotating tire which are used to determine if the tire is out of balance and, if so, by how much and the location of the out of balance condition on the tire. Once the operation of the balancer is complete, an out of balance position of the tire may be determined, and the controller <NUM>, in conjunction with the position signal generated by the read head <NUM>, will operate a marking system <NUM> to mark the appropriate spot on the tire sidewall indicating the location and balance condition of the tire. The marking system <NUM> is controlled via the signal designated generally by the capital letter G.

In operation, with reference to <FIG>, the balancer is shown in a locked default condition in <FIG> and <FIG> and an unlocked condition in <FIG> and <FIG>. In the default condition, the locking member <NUM> is received within the chucking assembly <NUM> and locked into position so that no extraneous forces can separate the locking member from the chucking assembly. In order to operate the balancer, the controller <NUM> will send a signal to the air supply <NUM> whereupon pressurized air is delivered to the spring-biased return cylinder <NUM>. This pressurized air causes the main cylinder to compress the cylinder spring <NUM> such that the cap surface <NUM> engages the shaft cap <NUM>, which in turn causes the spindle shaft <NUM> to axially move through the lower spindle <NUM>. This axial movement causes the inner sleeve <NUM>, which is attached to the spindle shaft, to move axially so as to compress the locking device spring <NUM>. This axial movement in turn causes the inner sleeve <NUM> to axially move the wedge sleeves <NUM> within the main spindle body <NUM>. This axial movement of the wedge sleeves results in the outward radial movement of the wedge jaws <NUM> and in turn the upper tees <NUM> as represented in <FIG>. As a result, the jaw teeth <NUM> disengage from the shaft teeth <NUM> wherein the jaw teeth were previously received in corresponding gaps <NUM> (see <FIG>). This disengagement allows for the locking shaft to be axially removed from the chucking assembly by the mechanism <NUM> as described above. The air coupling <NUM> and the coupling mate <NUM> are re-engaged to deflate the tire. Next, the linear actuator <NUM> retracts which causes the flange inner surface <NUM> to engage and lift the taper <NUM> so as to lift the locking shaft <NUM> out of the chucking assembly.

This axial removal separates the upper rim from the lower rim so that any tire received therebetween may be moved on to the next manufacturing station and allows for receipt of the next tire to be tested by the balancer. Once the next tire is preliminary positioned between the two rims, the controller <NUM> will determine the angular orientation of the locking member and the chucking assembly through the encoder assembly -- which knows the angular position of the chucking assembly, the spindle assembly, and the motor assembly. The controller <NUM> then adjusts the position of the spindle assembly through the motor assembly so that a home position is obtained whenever the locking member is received. This ensures consistency of the dynamic balancer test results. Next, the controller actuates the mechanism <NUM> to allow the actuator rod <NUM> to gradually lower the manifold <NUM> and the air coupling <NUM>. As a result, in a controlled manner, the air coupling <NUM> mates with the coupling mate <NUM> and the locking shaft <NUM> is lowered into the proper position within the chucking assembly. In other words, the locking shaft is lowered a specified distance to capture the tire, which has a known bead width between the two rims. The locking shaft is simultaneously received in the chucking assembly which is still in an unlocked position.

Next, the controller withdraws the pressurized air from the return spring cylinder which causes the chucking assembly to secure the locking shaft in position so as to capture the new tire in between the upper and lower rims. Specifically, withdrawing the air from the return spring cylinder allows the spindle shaft to return to its default position which in turn re-engages the chucking assembly with the locking member. Indeed, the wedge sleeves <NUM> are allowed to return to their original position which in turn moves the upper tees into engagement with the shaft (see <FIG>). Once the chucking assembly re-engages with the spindle assembly, the controller instructs the air supply to inflate the tire and also to further lower the inner surface <NUM> to no longer contact the taper <NUM> and disengage the air coupling <NUM> from the coupling mate <NUM> in such a way that the tire remains pressurized. Next, the power source <NUM> to deliver electrical power to the motor <NUM> which in turn initiates rotational movement of the rotor and the associated components of the main spindle. Accordingly, the motor assembly rotates the rotor at the desired speed and the rotational position is monitored by the encoder. Simultaneously, the load cells <NUM> detect forces generated by the particular tire received between the rims and this information is correlated with the rotational position information provided by the encoder. Upon completion of the test rotations by the spindle assembly, the controller determines whether the tire has an out of balance condition or not and then instructs the marking system <NUM> to mark the appropriate position on the tire. Skilled artisans will appreciate that the controller may send precise signals to the motor <NUM> so as to properly position the tire under the marking device of the marking system <NUM>. Upon completion of the marking operation, the above process is repeated so as to release the tire and move it on to its next manufacturing operation.

A number of distinct advantages are provided by the balancer disclosed herein. First, the locking member is provided with a non-circular cross section and in the present embodiment a square cross-section, so as to allow for the positive gripping of the locking member in a specific orientation. This permits significant gripping forces to be applied by the chucking assembly to the locking member so that it can be rotated at a significant speed without undue vibrations and/or stresses on the other components of the balancer. In the present embodiment, a home position may be utilized so that the locking member is always received within the chucking assembly at the same orientation. Skilled artisans will appreciate that this minimizes the determination of a characterizing force of the locking assembly when rotated at speed so as to accommodate any particular forces unique to the balancer.

Yet another advantage of the disclosed balancer is that the frameless motor assembly is utilized to rotate the spindle assembly. This is significant in that minimal extraneous forces are introduced by the motor assembly as the spindle assembly is not driven by a belt mechanism or other rotational feature that imparts extraneous forces during the detection of forces by the load cells. Still another advantage of the disclosed balancer is the employment of the return air cylinder which allows for positive engagement by the chucking assembly with the locking member. This is further facilitated by the non-circular cross section of the locking member and the use of positively engaging teeth between the chucking assembly and the locking member wherein those teeth easily engage with one another. The motor assembly is also advantageous in its construction in that cooling fins and heat conducting epoxy are utilized in its construction to dissipate the heat generated by the motor which allows for the application of higher power so as to rotate the rotor assembly and the spindle assembly at significantly higher speeds than found with other dynamic balancers.

Claim 1:
A dynamic balancer (<NUM>), comprising
an outer housing (<NUM>);
a spindle assembly (<NUM>) rotatably mounted to said outer housing (<NUM>) and having a spindle shaft (<NUM>);
a frameless motor assembly (<NUM>) comprising a stator (<NUM>) coupled to said outer housing (<NUM>) and a rotor (<NUM>) rotatably received within said stator (<NUM>) and connected to said spindle shaft (<NUM>);
a chucking assembly (<NUM>) receiving a locking member (<NUM>), said locking member (<NUM>) adapted to capture a tire therebetween, said chucking assembly (<NUM>) and said locking member (<NUM>) captured in said spindle assembly (<NUM>) and rotated by said frameless motor assembly (<NUM>); and
said spindle shaft (<NUM>) extending through said frameless motor assembly (<NUM>), one end of said spindle shaft (<NUM>) being adapted to axially move said chucking assembly (<NUM>) to engage and disengage said locking member (<NUM>) in said spindle assembly (<NUM>); and
an encoder assembly (<NUM>) comprising:
an encoder ring (<NUM>) connected to said rotor (<NUM>); and
a read head (<NUM>) adapted to be held in a fixed position to detect a rotational position of said encoder ring (<NUM>).