Valve grinding tool

A tool includes a coupling, an inner adjustment sleeve, and an outer adjustment sleeve. The coupling connects a rotary tool to the inner adjustment sleeve. An adjustable portion of the inner adjustment sleeve is threadedly received in the outer adjustment sleeve. An offset aperture in the free end of the outer adjustment sleeve receives a tip of a valve stem for grinding. An optional cup at the end of the outer adjustment sleeve stabilizes the tool. A grinding bit with a shaft retained in a collet of the rotary tool is contained internally, in a channel, extending through the tool.

FIELD OF THE INVENTION

This invention relates generally to internal combustion engines, and, more particularly, to a tool for grinding tips of poppet valves for appropriate clearance.

BACKGROUND

During a typical valve job, valve seats of the cylinder heads are resurfaced. Some cylinder heads have integral valve seats, while others have replaceable hardened steel valve seats. Replaceable valve seats can be removed and replaced. Integral seats are typically milled to allow the insert of a new seat. After resurfacing valve seats, the distance from the valve seat to the opposite side of the cylinder head may have decreased, which affects valve lash.

Valve lash or valve clearance is the gap between the rocker arms or bucket followers and the valve tip. In engines with rocker arms, a threaded rod or an eccentric at the end of each rocker arm adjusts the clearance to the top of the valve. In engines with overhead cams, bucket followers with calibrated shims, either above or below the buckets, are used to define the clearance. This clearance must be tightly controlled—too little and the valves may not seat properly, too much creates valve train noise and excess load on the valves and valve train components.

Often, after resurfacing valve seats and installing new valves, shims must be used to ensure proper height and clearance. As shims vary considerably in dimensions and configuration, and vary among corresponding followers, machinists must frequently order shims as needed. Maintaining an inventory of shims is impractical for many machinists. Ordering consumes time, which, means delayed job completion and delayed payment.

What is needed is a tool to precisely grind the tip of valves to provide proper clearance. The tool should be relatively inexpensive, easy to use and produce a tip with a planar top ground to a desired relative height.

The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above.

SUMMARY OF THE INVENTION

To solve one or more of the problems set forth above, in an exemplary implementation of the invention, a valve tip grinding tool includes a coupling, an inner adjustment sleeve (aka, threaded sleeve), a lock (jam) nut, and an outer adjustment sleeve (aka, alignment tube). The coupling connects a rotary tool to the inner adjustment sleeve. At least a portion of the inner adjustment sleeve is threadedly received in the outer adjustment sleeve. The extent received defines the length of the tool, which defines the depth of grinding. The free end of the outer adjustment sleeve includes an offset (not centered) aperture in which a tip of a valve stem is received for grinding. The aperture may be formed in an integral end of the outer adjustment sleeve or in an insert or cap that is removably attachable to the outer adjustment sleeve. A grinding disk is connected to a shaft or shank, which is retained in a collet of the rotary tool. The disk and shaft are contained internally, in a channel, extending through the tool.

In one embodiment, a spring cup is provided at the end of the outer adjustment sleeve. The spring cup receives a portion of a valve assembly. A tight fit between the cup and received portion of the valve assembly limits play. This helps ensure level planar grinding of the tip of the valve stem.

In some embodiment means for catching shavings are provided. Such means may include a cup-like structure formed in an interior channel of the tool and/or one or more magnets that extend into the interior channel of the tool adjacent to the grinding disk.

A valve grinding tool includes a coupler, a threaded sleeve and an alignment tube. The coupler includes a first end, a second end and a coupler central channel extending from the first end of the coupler to the second end of the coupler. The first end of the coupler is open and includes internal threads for connecting to a rotary tool (e.g., to a threaded collar of such a tool). The second end of the coupler is open and opposite to the first end of the coupler.

The alignment tube includes a first end, a second end and an alignment tube channel extending from the first end of the alignment tube to the second end of the alignment tube. The alignment tube has a central alignment tube longitudinal axis. The first end of the alignment tube is open and includes internal threads for connecting to the threaded sleeve. The second end of the alignment tube has an opening.

The threaded sleeve includes a central channel. The threaded sleeve couples the second end of the coupler to the first end of the alignment tube. A distance between the second end of the coupler and the first end of the alignment tube is adjustable by threadedly receiving a portion of the threaded sleeve in the central channel of the coupler and/or in the channel of the alignment tube. The central channel of the threaded sleeve has a central longitudinal axis.

The opening of the second end of the alignment tube has a center. The central longitudinal axis of the alignment tube threaded sleeve is not aligned with the center of the opening of the second end of the alignment tube. The opening of the second end of the alignment tube and the central channel of the alignment tube are sized to receive an end of a stem of a valve to be ground. The coupler central channel and alignment tube channel are sized to receive a grinding disk attached to a shank.

In this embodiment, the valve grinding tool is separate from the valve and from the stem of a valve to be ground. Also, in this embodiment, the valve grinding tool is separate from the grinding disk attached to the shank. Additionally, in this embodiment, the valve grinding tool is separate from the rotary tool.

Optionally, a lock nut may be provided on the threaded sleeve.

Markings (e.g., indicia) may be provided to indicate the length of the tool and/or the extend (e.g., depth) of grinding. For example, the valve grinding tool may have a first indicium on the threaded sleeve adjacent to the alignment tube, and a second indicium on the alignment tube adjacent to the threaded sleeve. When the first indicium is aligned with the second indicium, the first end of the alignment tube is a first (e.g., known) distance from the second end of the coupler. Many such indicia may be provided to indicate various lengths or depths.

In one embodiment, the second end of the alignment tube includes a cover in which the opening of the second end of the alignment tube is formed as an aperture. The central alignment tube longitudinal axis is not aligned with the center of the opening of the second end of the alignment tube.

In another embodiment, the alignment tube channel includes a first portion and a second portion. The first portion extends from the first end of the alignment tube and has a first central longitudinal axis. The second portion extends from the second end of the alignment tube to the first portion of the alignment tube channel and has a second central longitudinal axis. The first central longitudinal axis is not aligned with the second central longitudinal axis.

In another embodiment, the alignment tube magnetically retains grindings. For example, at least one magnet may be attached to the alignment tube. Alternatively, the alignment tube may be comprised of a magnetized ferromagnetic material.

In another embodiment, an optional spring cup extends from the second end of the alignment tube. The spring cup engulfs the exposed portion of a valve spring.

In another embodiment, the outer diameter of the alignment tube is less (e.g., slightly less [no more than 2% less]) than an inner diameter of a cup-shaped cam follower to be ground. In this embodiment, the disc of the grinding tool is positioned near the second end of the alignment tube and the cam follower cup may be slid onto the end of the alignment tube. Thus, in this embodiment, the portion of the cam follower cup that extends into the alignment tube may be ground level.

In another embodiment, a rotary tool and grinding disk assembly are included to provided a valve grinding system. The rotary tool includes a motor, threaded collar and a chuck coupled to the motor. The grinding disk assembly includes an abrasive disk attached to a shank. The shank is retained in the chuck of the rotary tool. The alignment tube channel is sized to receive the abrasive disk attached to the shank of the grinding disk assembly.

DETAILED DESCRIPTION

With reference toFIGS. 1 through 6, an exemplary valve grinding tool100according to principles of the invention includes a coupling105, an inner adjustment sleeve120, a lock nut115, and an outer adjustment sleeve130. The coupling105is a sleeve (i.e., a structure with a central cylindrical channel112extending from end110to end114). One end110of the coupling105receives and threadedly engages a threaded nose410of a rotary tool400(FIG. 12). The opposite end114of the coupling105receives and threadedly engages an end113of the inner adjustment sleeve120. Thus, the function of the coupling105is to couple a rotary tool400to the inner adjustment sleeve120.

The inner adjustment sleeve120of the exemplary tool100is a sleeve with external threads. A central channel155extends through the sleeve120. The inner surface of the channel155may be smooth or threaded, as shown inFIGS. 5 and 6. However, inner threads are not necessary unless another component is configured with an externally threaded male component that is received within and threadedly mates with the inner adjustment sleeve120.

An outer adjustment sleeve130extends from the inner adjustment sleeve120, opposite to the coupling105. The outer adjustment sleeve130is a sleeve with a central channel and internal threads that mate with the external threads of the inner adjustment sleeve120. One end135of the outer adjustment sleeve130is open, and receives and threadedly engages an end of the inner adjustment sleeve120. In the embodiment shown inFIGS. 1 through 6, the opposite end includes a cover140with a circular cross section aperture142(shown inFIGS. 4 through 6) sized to receive a tip of a valve stem to be resurfaced (i.e., ground).

As evident inFIGS. 3 and 4, the aperture142in the cover140of the outer adjustment sleeve130is off-center, meaning that its center is not aligned with the center of the outer adjustment sleeve130. This off-center configuration facilitates grinding. During use, a rotating grinding disk is contained within the outer adjustment sleeve130near the cover140. Grinding proceeds more effectively when the surface being ground is positioned away from the center of the disk, towards the peripheral edge of the disk. The cross-radial (tangential) velocity (v) of the surface of the disk grinding the tip of valve increases with distance from the center, r, and with rotational velocity, ω, as in v=rω. The aperture142is positioned off-center relative to the center of the outer adjustment sleeve130to ensure effective grinding of the tip of the valve stem, by providing a non-zero tangential velocity. By way of example and not limitation, given a radius, ro, of the outer adjustment sleeve130, the center of the aperture142is positioned at a×ro, where 0<a<1, and more preferably 0.1<a<0.7, and even more preferably 0.2<a<0.5.

A jam nut115is provided on the inner adjustment sleeve120. It is used as a lock nut. When tightened (jammed) against the outer adjustment sleeve130, the jam nut115prevents unintended rotation and motion of the outer adjustment sleeve130relative to the inner adjustment sleeve120. While a nut with polygonal (e.g., hexagonal) periphery is shown, other nut-like members, including knurled nuts may be used in addition to, or in lieu of, the depicted jam nut115. Additionally, more than one jam nut may be provided for the outer adjustment sleeve130and the coupling105.

The pitch of the threads on the inner adjustment sleeve is x threads per inch. One revolution of the outer adjustment sleeve relative to the inner adjustment sleeve advances the outer adjustment sleeve toward or away from the coupling precisely 1/x″. Markings145on the edge of the outer adjustment sleeve indicate partial rotations relative to a marking125on the inner adjustment sleeve, for fine adjustment. By way of example and not limitation, the reading lines145may be divided into y equal parts (e.g., 360°/y) that correspond to the number of increments in a full rotation. Therefore, each reading line may indicate indicates 1/(x×y)″ relative movement. Illustratively, if, by way of example, x is 10 (i.e., there are 10 threads per inch) and there are 36 markings145, i.e., one marking every 10°, then a rotation of one marking is 1/36 of a full rotation, which corresponds to 1/360 inches, or 0.00278 inches.

As stray metal particles in a valve assembly or cylinder head could interfere with valve movement and seating and accelerate wear, collecting particles is desirable. As most clearly evident in the section view ofFIG. 6, a collection cup152may be formed in the interior of the outer adjustment sleeve130. The collection cup152surrounds the aperture142. The collection cup152is a bundt pan shaped container, with the central opening being the aperture142. The collection cup is defined by a raised cylindrical wall150extending inwardly from the aperture142. The aperture142and cylindrical wall150have the same or nearly the same radius. The base and outer wall of the bundt pan shaped container are defined by the cover140and the outer adjustment sleeve130. During use, metal particles ground from a valve tip collect in the collection cup152. The collected particles will therefore not fall into the valve assembly or cylinder head.

FIGS. 7 through 9illustrate an embodiment of the tool100with a spring cup160. One end165(i.e., a covered end) of the cup160attaches to an end140of the outer adjustment sleeve130. The opposite end170of the cup160is open. The diameter of the cup160is slightly larger than the diameter of a valve assembly, as described below. The depth (length) of the cup is sufficient to receive the valve assembly to about a spring seat, as described below. In this embodiment, the cover140, aperture142, collection cup152, and cylindrical wall150are not necessary.

To maintain the off-center relationship discussed above, the center (a longitudinal axis extending through the center) of the outer adjustment sleeve130is not aligned with the center (a longitudinal axis extending through the center) of the cup160. The tip of a valve stem will extend into the cup parallel to and in alignment with a longitudinal axis extending through the center of the cup160. The tip is preferably not aligned with the center (a longitudinal axis extending through the center) of the outer adjustment sleeve130. By way of example and not limitation, given a radius, ro, of the outer adjustment sleeve130, the center of the cup160is positioned at a×ro, where 0<a<1, and more preferably 0.1<a<0.7, and even more preferably 0.2<a<0.5.

FIGS. 10 and 11illustrate the exemplary valve tip grinding tool ofFIG. 7with a valve assembly according to principles of the invention. The valve assembly200includes a poppet valve205with a valve stem and a tip225to be ground, and a spring210between a spring seat215and retainer220. The cup160is sized to slide over the top of the assembly up to about the spring seat215, as conceptually illustrated inFIG. 11. The spring210, retainer220and tip225are received in the cup160. The tip225is received up to about the inside of the covered end165. A grinding disk extends into the cup between the tip225and the inside of the covered end165. As the inner diameter of the cavity of the cup160is only slightly larger than the spring210diameter, the fit provides very little room for play. Thus, the cup160prevents undesirable tilting of the tool100during use.

FIG. 12is a front view of an exemplary rotary tool400with an abrasive grinding bit300for use with a valve tip grinding tool100according to principles of the invention. The grinding bit includes a shaft305or shank and a cylindrical cross section disk310with an abrasive grinding surface. The shaft305is secured in a collet (i.e., a chuck that forms a collar around the shaft and exerts a strong clamping force on the shaft when it is tightened) of the rotary tool400. The rotary tool400includes a housing405with a threaded nose410. In some rotary tools, a removable ring-like threaded cover is provided on the nose410. Any such ring-like threaded cover must be removed to expose the threaded nose410.

As shown inFIG. 13, the threaded nose410of the rotary tool400threads into the coupling105. The cup160slides over the top of a valve assembly200up to about the spring seat215. The spring210, retainer220and tip225are received in the cup160. The tip225is received up to about the inside of the covered end165. A grinding disk310extends into the cup160between the valve tip225and the inside of the covered end165. As the inner diameter of the cavity of the cup160is only slightly larger than the spring210diameter, the fit provides very little room for play. Thus, the cup160prevents undesirable tilting of the tool100during use.

To adjust the depth of grinding, the outer adjustment sleeve130may be rotated relative to the inner adjustment sleeve120, with rotation in one direction decreasing the distance between the coupling105and cup160, and therefore increasing the depth of grinding, and rotation in the opposite direction increasing the distance between the coupling105and cup160, and therefore decreasing the depth of grinding. The depth may be carefully calibrated using the markings125,145, as discussed above.

Grinding may proceed until the tool100bottoms out on a surface of the valve assembly200. By way of example, the cup160may bottom out on a spring seat215. Alternatively, in the embodiment ofFIG. 1, the bottom140of the outer adjustment tube130may bottom out against the spring retainer220of the valve assembly200.

FIG. 14is a perspective view of another exemplary valve tip grinding tool100with removable magnetic shaving catchers according to principles of the invention. The magnetic shaving catchers comprise screws600,605,610, each having a screw head615,620,625and a threaded shank that terminates with a magnet at the free end of the shank630,635,640. While three screws and corresponding threaded holes are illustrated in the perspective view ofFIG. 14, the invention is not limited to any number of such screws and holes. Rather, such screws are optional. An embodiment of the invention may include zero, one or more such screws and corresponding holes. The screws threaded into corresponding threaded holes645,650,655in the top of the cup160. However, they may be configured to thread into other areas (e.g., the sidewall) of the cup160without departing from the scope of the invention. The magnets catch (i.e., magnetically attract and hold) metal shavings (typically steel shavings) propelled during grinding action. Each magnet is preferably a permanent magnet, made from a material that is magnetized and creates its own persistent magnetic field. In an exemplary embodiment, the magnet is a ceramic, or ferrite, magnet made of a sintered composite of powdered iron oxide and barium/strontium carbonate ceramic; or an alnico magnet made by casting or sintering a combination of aluminum, nickel and cobalt with iron and other elements; or a rare-earth magnet, such as a samarium-cobalt or neodymium-iron-boron magnet. The magnet may be coated (e.g., nickel or zinc plated or epoxy coated) to enhance durability and corrosion resistance.

The embodiment ofFIG. 14also reveals a knurled jam nut515, and a knurled threaded end146of the outer adjustment sleeve130, to which the cup160is threadedly attached. Additionally, inFIG. 14, the inner adjustment sleeve120is substantially received within the outer adjustment sleeve130, and therefore not apparent in the drawing.

In the embodiment ofFIGS. 15 and 16, the cup160is replaced with a cup700that includes a removable threaded cap715. The cup700includes a male threaded top750that is received within the female threaded compartment735of the cap715. The cap includes a male threaded collar725to thread into the end140of the outer adjustment sleeve130. An aperture740is provided through the collar725to the interior of the cup700. One or more magnets745is fastened (e.g., mechanically fastened or bonded) to the interior of the cap715. The magnet catches steel shavings from the grinding process. In the exemplary embodiment, one ring-like magnet745concentric with the aperture740is shown. The removable cap715facilitates cleaning the caught shavings from the magnet after use. The cap715is shown with a hexagonal periphery that can be gripped with a wrench to facilitate installation and removal.

The magnet(s)745is (are) a permanent magnet, made from a material that is magnetized and creates its own persistent magnetic field. In an exemplary embodiment, each magnet is a ceramic, or ferrite, magnet made of a sintered composite of powdered iron oxide and barium/strontium carbonate ceramic; or an alnico magnet made by casting or sintering a combination of aluminum, nickel and cobalt with iron and other elements; or a rare-earth magnet, such as a samarium-cobalt or neodymium-iron-boron magnet. The magnet may be coated (e.g., nickel or zinc plated or epoxy coated) to enhance durability and corrosion resistance.

Referring now toFIGS. 17-20an exemplary valve grinding tool800includes a coupler808, a threaded sleeve815and an alignment tube822. The coupler808includes a first end805, a second end810and a coupler central channel extending from the first end of the coupler to the second end of the coupler. The first end805of the coupler808is open and includes internal threads for connecting to a rotary tool (e.g., to a threaded collar of such a tool). The second810end of the coupler808is open and opposite to the first end805of the coupler810. A set screw802may be provided near the second end of the coupler808to secure the second end810of the coupler805to an end of the threaded sleeve815.

The alignment tube822includes a first end820, a second end825and an alignment tube channel extending from the first end820of the alignment tube to the second end825of the alignment tube. The alignment tube822has a central alignment tube longitudinal axis. The first end820of the alignment tube822is open and includes internal threads for connecting to the threaded sleeve815. The second end825of the alignment tube822has an opening.

The threaded sleeve815includes a central channel. The threaded sleeve couples the second end810of the coupler808to the first end820of the alignment tube822. A distance between the second end of the coupler and the first end of the alignment tube is adjustable by threadedly receiving a portion of the threaded sleeve815in the central channel of the coupler808and/or in the channel of the alignment tube822. The central channel of the threaded sleeve815has a central longitudinal axis.

The opening of the second end825of the alignment tube822has a center. The central longitudinal axis of the threaded sleeve855is not aligned with the center of the opening of the second end825of the alignment tube822. The opening of the second end825of the alignment822tube and the central channel of the alignment tube822are sized to receive an end (e.g., tip) of a stem of a valve to be ground. The coupler central channel and alignment tube channel are sized to receive a grinding disk attached to a shank.

In this embodiment, the valve grinding tool800is separate from from the stem of a valve to be ground. The valve stem may be inserted when ready for grinding. Also, in this embodiment, the valve grinding tool800is separate from the grinding disk attached to the shank. The grinding disk on the shank may be inserted when ready to commence grinding. Additionally, in this embodiment, the valve grinding tool is separate from the rotary tool. The rotary tool may be attached when ready for grinding.

The alignment tube channel includes a first portion and a second portion. The first portion extends from the first end820of the alignment tube822and has a first central longitudinal axis. The second portion extends from the second end825of the alignment tube822to the first portion of the alignment tube channel and has a second central longitudinal axis. The first central longitudinal axis is not aligned with the second central longitudinal axis.

In another embodiment, the alignment tube magnetically retains grindings. For example, at least one magnet830may be attached to (e.g., pressed into an aperture in) the alignment tube. Alternatively, the alignment tube may be comprised of a magnetized ferromagnetic material.

In another embodiment as shown inFIG. 21, the outer diameter of the alignment tube826is less (e.g., slightly less [no more than 2% less]) than an inner diameter of a cup-shaped cam follower835to be ground. In this embodiment, the disk of the grinding tool is positioned near the second end828of the alignment tube826and the cam follower cup835may be slid onto the end of the alignment tube826towards the first end824of the alignment tube826. Thus, in this embodiment, the portion of the cam follower cup835that extends into the alignment tube828may be ground level.

In one embodiment, a rotary tool and grinding disk assembly are included to provided a valve grinding system. The rotary tool includes a motor, threaded collar and a chuck coupled to the motor. The grinding disk assembly includes an abrasive disk attached to a shank. The shank is retained in the chuck of the rotary tool. The alignment tube channel is sized to receive the abrasive disk attached to the shank of the grinding disk assembly.

While an exemplary embodiment of the invention has been described, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum relationships for the components and steps of the invention, including variations in order, form, content, function and manner of operation, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. The above description and drawings are illustrative of modifications that can be made without departing from the present invention, the scope of which is to be limited only by the following claims. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents are intended to fall within the scope of the invention as claimed.