US3564697A

US3564697A - Collet lock removal tool

Info

Publication number: US3564697A
Application number: US813835A
Authority: US
Inventors: John H Shalaty; Herbert W Arp
Original assignee: TRW Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1969-04-07
Filing date: 1969-04-07
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23

Abstract

A TOOL FOR REMOVING MULTI-FINGER INTERNALLY BEADED COLLECT FROM GROOVED STEMS WHICH HAS A STEM RECEIVING HOLLOW HEAD WITH FORWARDLY PROJECTING TAPERED TABS ADAPTED TO ACT BETWEEN THE STEM AND EACH FINGER OF THE COLLET FOR EXPANDING THE FINGERS SUFFICIENTLY SO THAT THEIR BEADS WILL NOT ENGAGE IN THE GROOVE OF THE STEM AND ALSO HAVING AN INDEXING PRONG FITTING IN A SLOT BETWEEN ADJACENT FINGERS FOR POSITIONING THE TABS AT THE MIDPOINTS OF THE FINGERS. THE TOOL IS ESPECIALLY ADAPTED FOR REMOVING LOCK AND SPRING RETAINER ASSEMBLIES FROM GROOVED POPPET VALVE STEMS.

Description

Feb. 23,l 1971 J, H SHALATY ET AL 3,564,697

`COLLET LOCK REMOVAL TOOL Filed April v, 1969 2 Sheetssheet 1 M l O f? #ma/@wx Feb. 23, 1971 H, SHALATY ET AL 3,564,697

COLLET Loox REMOVAL TooL Filed April 1969 2 Sheets-sheet 2 /NvliNf/ORS JOA/A/ S/JAL ATY United States Patent O 3,564,697 COLLET LOCK REMOVAL TOOL John H. Shalaty, Wicklie, and Herbert W. Arp, Chardon,

Ohio, assignors to TRW Inc., Cleveland, Ohio, a corporation of Ohio Filed Apr. 7, 1969, Ser. No. 813,835 Int. Cl. B23p 19/04; B251: 27/24 U.S. Cl. 29-249 8 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to the tool art and particularly to a hand tool for removing collets from members locked thereto. The invention will be hereinafter specifically described as embodied in a hand tool for removing one piece valve stem lock and spring retainer cap assemblies from grooved valve stems, but it should be understood that the principles of this invention are not limited to this particular usage being generally applicable to the expanding of collets off of members gripped thereby.

DESCRIPTION OF THE PRIOR ART Hand tools for removing one piece valve look and retainer assemblies from the stems of grooved poppet valves are known in the prior art, for example in the Max I. Tauschek U.S. Pat. 3,284,887 dated Nov. 1S, 1966. In the T auschek patent, the multi-finger internally beaded valve lock is expanded to slide off of the valve stem by wedging prongs or teeth projecting from the end edge of a hollow tool head to enter the slots between the spring fingers of the lock. The teeth or prongs have outer surfaces which converge radially inward to their tip ends for wedging in the conical bore of the spring retainer to depress the retainer relative to the lock. The teeth enter into the slots between the lock fingers and have diverging side walls increasing the widths of the slots and thereby expanding the fingers so that their internal beads will slide past the valve stem groove. Since the teeth wedge fit in the bore of the retainer and between the spring fingers, galling of the retainer and lock can occur and the fingers wear rapidly to dimensions inadequate for sufficiently spreading the fingers so that their beads will slide past the valve stem groove. Further, an accurate mating of the tool teeth, retainer bore, and finger slots is required which restricts the effectiveness in the tool for use in commercial installationsr where tolerances vary considerably.

SUMMARY OF THE INVENTION The present invention now avoids the necessity for accurately mating collet removal tools with the assemblies on which they are to be used, and prevents galling and damage to these assemblies.

According to the present invention a tool is provided with a hollow end head with an internal bore sized for freely embracing a valve stem. The forward end 3,564,697 Patented Feb. 23, 1971 ICC edge of this head has circumferentially spaced forwardly projecting radially tapered tabs for fitting between the central portions of the collet fingers and the valve stem. In addition, the tool has an indexing prong radially outward from and circumferentially between two adjacent tabs for seating in a slot between two adjacent lock fingers to thereby position the tabs at the rnidpoints of each finger. The indexing prong extends forwardly from the tabs so that it will first enter the slot before the tabs engage the lock fingers. The tabs have considerable circumferential length to smoothly slide over the valve stern and under the lock fingers. The tabs do not engage the bore of the retainer. Galling and damage to the retainer and lock is thereby prevented.

When the lock fingers are circumferentially wedged by the tapered bore of the retainer around the valve stem, they grip the valve stem more tightly at their circumferential extremities than at their midpoints. The indexing prong of the tool of this invention locates the expanding tabs so that they enter between the valve stem and finger at the midportions of the fingers where the widest openings will occur. This is accomplished by positioning the indexing prong equidistance between the two adjacent tabs.

To effect removal of the lock and retainer assembly from a valve stem, the retainer is depressed so that the top of the lock will project beyond the retainer with the fingers positioned in the wide end of the tapered retainerbore. The valve and lock assembly is pushed down on the valve stem beyond the groove. The tool of this invention is then applied over the free end of the valve stem to a depth bottoming the index prong on the lock whereupon the tool is rotated to drop the prong into a slot between two fingers of the lock. The tabs are then aligned with the midpoints of the fingers and the tool is lightly tapped to force the tabs under the lock fingers causing them to spread and move their internal beads to a diameter sufiiciently large to clear the valve stem. The lock and retainer assembly is then lifted off of the valve stem rwith the tool.

It is then an object of this invention to provide a hand tool which simply and easily removes collet assemblies from members gripped thereby without galling or wear.

Another object of this invention is to provide a hand tool for removing one piece valve lock and spring retainer assemblies from grooved valve stem without engaging the bore of the retainer and without damaging the lock fingers.

A still furthel object of this invention is to provide an improved tool for removing valve lock and retainer assemblies from grooved valve stems which tool has wide tabs embracing the valve stem and entering under the fingers of the lock.

Another object of this invention is to provide a valve lock removing tool with an indexing prong preventing misuse of the tool.

A further and specific object of the invention is to provide a valve lock removal tool having a hollow cylindrical head with circumferentially spaced wide tabs projecting axially therefrom and with an indexing prong spaced radially outward from the tabs and about midway between two adjacent tabs.

Other and further objects of the invention will be apparent to those skilled in this art from the following detailed description of the annexed sheets of drawings which, by way of a preferred embodiment, illustrates one example of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged longitudinal cross-sectional View of the head end of the tool of this invention with a portion of the handle broken away;

FIG. 2 is an end elevational view of the head end of the tool of FIG. 1;

FIG. 3 is a perspective view of the type of valve lock removed by the tool of this invention;

FIG. 4 is a vertical cross-sectional, with parts in elevation, of an engine valve assembly including a one-piece valve lock and spring retainer cap assembly of the type removed by the tool of this invention;

FIG. 5 is an enlarged fragmentary sectional View, with a part in elevation, of the valve stem and lock assembly of FIG. 4 showing the first step in the removing operation;

FIG. 6 is a view similar to FIG. 5 but showing the application of the tool of this invention for the removal operation; and

FIG. 7 is a transverse sectional view on an enlarged scale taken along the lines VII-VII of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT The tool 10 shown in FIG. l of this invention includes a generally cylindrical handle or grip 11 with a well 12 extending axially inward from an end face 13 to a sufiicient depth for firmy anchoring a hollow cylindrical tool body or shank 14. The body 14 has an integral collar 15 bottomed on the end face 13 and a portion 14a on one side of the collar firmly seated in the well 12 to unite the handle and body. The body has a portion 14b on the other side of the collar projecting forwardly from the end face 13 of the handle a sufiicient distance to provide a convenient tool working len-gth. The body 14 has a straight cylindrical bore 16 therethrough of a diameter sufficient to freely embrace a valve stem while at the same time guiding the tool in an upright parallel relationship with the valve stern.

The forward end of the body 14 has a reduced diameter portion 14C terminating in a radial shoulder 14d. A sleeve 17 surrounds this portion 14C and is bottomed on the shoulder 14d. The sleeve is shrunk tit, welded or otherwise integrally united with the tool body 14. The reduced diameter body portion 14C projects beyond the sleeve 17 and is beveled on its outer circumference to provide the working end or head 18 of the tool. This head end includes a complete tapered ring portion 19 with circumferentially spaced slots 20 extending inwardly from the leading thin edge thereof to about the axial midpoint of the tapered head. These slots provide three circumferentially spaced tabs 21 with thin leading end edges. The tabs increase in radial depth to the continuous ring beveled portion 19 which in turn increases in radial depth to the outer end edge of the sleeve 17. The end view of FIG. 2 shows the tabs 21 as having thin end edges 21a with diverging outer tapered or beveled outer side walls and straight cylindrical inner walls. The cut-out portions 20 .are shown extending circumferentially between the end edges 2lb of the tabs to a depth in the thicker portion provided by the continuous tapered ring surface portion 19.

The head end 18 of the tool thus has three circumferentially spaced axially projecting accurate tabs 21 with thin leading end edges 21a, axial side edges 2lb, tapered outer side faces diverging from the thin edges 21a to the continuous tapered ring portion 19 and straight cylindrical inner faces.

The body 14 is preferably made of metal while the handle can be plastic, wood or metal.

The sleeve 17 has a prong 22 extending axially from its end edge beyond the axial extremities of the tabs 21. The prong 22 is tapered along its length to provide a reduced leading nose end 22a. The prong 22 is positioned radially outward from and about midway between two of the tabs 21.

From the above description it will therefore be understood that the tool is a simple member with a handle and a hollow shank having an active end head with three cir- 4 cumferentially spaced tabs which diverge from thin leading edges to a continuous diverging ring and which has an indexing pron-g midway between two of the tabs and radially outward therefrom. It should also be understood that the number of tabs will correspond with the number Of collet leaves or fingers to be removed.

The tool 10 is especially useful in removing a valve lock and spring retainer assembly 25 from a conventional poppet valve assembly 26 on an engine 27, as shown in FIG. 3. As therein illustrated the engine had a head 28 with a valve port 29 controlled by a poppet valve 30 coacting with a valve seat 31 to control flow between the engine combustion chamber 32 and the port 29. The valve 30 has a head 30a seating on the seat 31 and an elongated grooved stern 30b slidably guided in a valve guide 33 carried by the engine head 28. The groove 30C of the stem is located near the top tip end of the stem and has a radial top shoulder 34 and a beveled bottom shoulder 35.

The lock and retainer assembly 25 includes a spring retainer cap 36 with a tapered collar 36a surrounding the valve stem and a radial flange 36b providing a shoulder against which the valve closing spring 37 is seated. The spring 37 is compressed between the engine head and the retainer cap.

The collar 36a has a frustoconical or tapered bore 38 converging from the top to the bottom of the retainer cap.

A one-piece valve lock 39 is seated in this bore 38. As shown in FIG. 3, the valve lock 39 is tubular with a cylindrical bottom portion 39a that may be split and have the split ends abutted together as at 40. Three spring fingers or leaves 39b separated by vertical slots 41 project upwardly from the cylindrical base 39a. These fingers are tapered and increase in thickness from the base 39a to the top of the lock. The tapered outer surfaces of the fingers fit in the bore 38 of the cap 36. Each finger 39b has an inwardly projecting bead 39e extending circumferentially thereof for projecting into the groove 30e of the valve stem 30'b.

The cylindrical base 39a of the lock projects beyond the collar 36a of the retainer cap and its bottom edge is out-turned at 39b to a diameter greater than the small end of the bore 38 so that the lock is retained in assembled position in the cap 36 but is free to slide in the bore 38 of the cap.

When the valve spring 37 acts on the cap 36, the bore 38 will draw the spring lingers 39b together causing them to tightly grip the valve stem with their beads 39C seated in the stem groove. The cap is thereby locked fixedly to the valve stem at the level of the stem groove and the radial shoulder 34 of the stem groove prevents the beads 39C from slipping out of the groove in an upward direction. On the other hand, the beveled bottom shoulder 3S of the groove will accommodate the slipping of the beads downwardly on the stem past the groove when spring ten- Sion is released from the cap and the fingers 39o are allowed to expand in the bore 38.

As illustrated in FIG. 5, when a downward force F is applied to the retainer cap 36, the lock 39 gripping the Valve stem 30b will tend to hold the position of FIG. 4 until the retainer cap 36 slides downwardly on the lock against the out-turned flange 39d, whereupon the spring fingers 39b will be positioned in the large end of the bore 38 and free to expand. Then this downward force F on the retainer cap 36 will pull the lock 39 downwardly with the cap with the beads 39C of the lock sliding out of the groove over the inclined shoulder 35 to be bottomed on the full diameter of the valve stem 30b as illustrated in FIG. 5. In this position of the lock 39 the spring fingers 39b are spread apart and gaps 42 are opened up between the tops of the spring fingers and the valve stern as shown in FIGS. 5 and 7. Since the contracting force on the spring fingers 39b exerted by the tapered bore 38 wraps these fingers around the valve stem in the locked position of FIG. 4, these gaps 42 have their widest dimension at the circumferential midpoints of the lingers.

With the assembly 25 in the position of FIG. 5, the tool 10 is applied for removing the assembly from the valve stem as illustrated in FIG. 6. As there shown, the tool shank 14 freely embraces the valve stem 30b receiving the tip end of the valve stem in the bore 16 thereof. The tool is rotated to position the indexing prong or pin 22 on the active end 18 thereof in one ofthe slots 41 between two adjacent spring lingers 39b as shown in FIG. 7, and the tabs 21 of the tool are then aligned with the widest portions of the gaps 42 to enter therein upon application of the downward force to the tool. This will position the tabs 21 between the valve stem 3011 and the spring fingers 39h as shown in FIG. 6 and the tapered outer faces 2lb of these tabs will spread the fingers apart so as to maintain the beads 39e radially outward from the valve stem. Then the entire assembly 25 is easily withdrawn from the valve stem with the tool because the fingers 39C will not reenter the groove 30C or strike against the radial shoulder 34 of the valve stem.

Therefore, the removal of the assembly 25 from the valve locking position of FIG. 4 is easily accomplished by depressing the retainer cap 36 to carry the lock 39 therewith to the position of FIG. on the valve stem and then the tool is applied over the end of the valve stem with its tabs entering the gaps between the valve stem and lock lingers to expand the fingers and hold them in a position so that their beads cannot reenter the stem groove as the tool and assembly are retracted off of the end of the valve stem.

The tabs 21 have leading ends which are thin enough so that they may enter the minimum space or gap 42 between the valve stem 30b and the lingers 39h, since an uneven spacing may occur at the midpoints of the ngers when the lock is forced over the valve stem before the beads of the lingers enter the stem groove. Further, the slots 41 between the fingers may be of unequal width as a result of practical production tolerances and the index prong 22 should be narrow enough at its leading end to enter at least one slot 41 since the tool is easily rotated until the prong drops into a slot capable of readilv receiving the leading end of the prong.

From the above descriptions it will be understood that the tool 10 simply and easily removes a collet lock from its gripping relation to an inserted member and is especially useful in removing valve locks from grooved valve stems without damaging the stems or locks.

We claim:

1. A tool for removing multi-linger internally beaded collets from grooved stems which comprises a hollow shank adapted to freely embrace the stem containing the collet, said shank having a head end with a projecting index pin adapted to t between fingers of the collet, said head end having circumferentially spaced tapered tabs radially inward from said index pin with thin leading edges adapted to enter between the stem and collet lingers and diverging outer walls for acting on the spring fingers to spread the same apart as the tabs are forced between the fingers and stem.

2. A hand tool for removing valve stem lock and spring retainer assemblies from grooved valve stems which comprises a handle, a hollow shank projecting from said handle, a reduced diameter end portion on said shank, a sleeve embracing said reduced diameter end portion in fixed relation and having a depending indexing pin projecting beyond the end of the shank, said shank having a beveled portion projecting beyond said sleeve, said beveled portion being slotted to provide circumferentially spaced tapered tabs at the end of the shank, and said indexing pin being aligned midway between two of the tabs and radially outwardly therefrom.

3. A hand tool for removing collets from stems which comprises a handle, a hollow shank projecting from the handle, a beveled end on said shank, slots separating said beveled end into circumferentially spaced tapered tabs, and an index pin projecting from said shank radially outward from said tabs and circumferentially spaced therefrom to align the tabs for expanding the collet olf of the stern.

4. The hand tool of claim 1 wherein the shank is cylindrical, the end of the shank is beveled on its outer circumference only and the tabs have thin leading ends diverging to thicker root portions.

5. The tool of claim 1 wherein the index pin is aligned radially outward from and circumferentially between two of the tabs.

6. The hand tool of claim 2 wherein the active end of the shank has three tabs with cylindrical inner faces and tapered outer faces diverging from thin leading edges to thick root portions.

7. The hand tool of claim 2 wherein the indexing pin is axially tapered to provide a narrow leading end.

8. The hand tool of claim 3 wherein the active end of the tool is a tapered cylinder with axially projecting circumferentially spaced prongs.

References Cited UNITED STATES PATENTS 3,284,887 11/1966 Tasuchek 29-249 3,314,136 4/1967 Giles 29-249 ANDREW JUHASZ, Primary Examiner L. GILDEN, Assistant Examiner U.S. Cl. X.R. 29-272, 280