CA2312125A1 - Valve spring compressor - Google Patents

Abstract

A valve spring compressor is provided for compressing valve springs in a cylinder head assembly so that a selected valve can be released and removed for repair or replacement. The valve spring compressor includes an adjustable C-shaped frame defining opposing jaws, the first jaw having a foot adapted to engage a spring retainer but adapted to move past a rod end of the valve, the second jaw being adapted to engage a valve-sealing end of the valve. A power-assisted actuator (in the form of a piston and extendable rod) and a manual control (in the form of a manually shiftable spool valve) is incorporated into a housing in the second jaw in a manner forming an integral handle.
The manual control is movable to first, second, and third positions where the rod is retracted, extended, or located in an intermediate position. The first jaw has an apertured foot adapted to engage the retainer but adapted to move past the rod end. The foot has a concave retainer-engaging surface that is adapted to stably nestingly engage the retainer despite a specific size of the retainer and valve spring being unknown ahead of time. The C-shaped frame is adjustable and includes first and second subframes. The second subframe slidably engages the first subframe, and a finger-operated trigger lock releasably engages the first subframe to permit quick adjustment of the first subframe relative to the second subframe.

Description

VALVE SPRING COMPRESSOR
BACKGROUND OF THE INVENTION
The present invention relates to valve spring compressors, and more particularly relates to an adjustable valve spring compressor that is adapted to compress valve springs on different cylinder head constructions despite different valve spring designs.
Valve spring compressors are well known in the art for removing the relatively stiff valve springs in cylinder heads of conventional automotive engines.
Preferably, valve spring compressors are made sturdy enough to withstand repeated usage and yet lightweight and balanced for convenient handling by a mechanic. Typically, the tool has opposing jaws that are adapted to be positioned at opposite ends of a selected valve, one jaw being positioned over a valve spring and another jaw being positioned under the cylinder head. An initial adjustment is performed in order to match the general spacing of jaws to the valve spring and the cylinder head, and then the tool is actuated to compress the selected valve spring. The compressed spring allows collets holding a spring retainer on the valve to be removed, so that the spring retainer, and in turn the valve spring and valve, can be removed. The operation is reversed for re-assembly.
However, cylinder heads and valves are designed in many different shapes and sizes, and valve retainers and valve springs are also designed in many different diameters, such that it is difficult to design a single valve spring compressor that will work on most valve arrangements. As a result, a valve spring compressor is needed that provides greater adjustability, greater flexibility, greater adaptability, and that is easier to use. Further, a valve spring compressor is desired that maintains a balance and low weight for convenient handling, but also that provides a simple and low cost mechanism with high durability.
Accordingly, a valve spring compressor solving the aforementioned problems and having the aforementioned advantages is desired.
SUMMARY OF THE PRESENT INVENTION
A valve spring compressor is provided for compressing valve springs in a cylinder head assembly so that a selected valve can be released and removed for repair or replacement. Cylinder head assemblies typically include a plurality of valves, each having a port-engaging end and a rod end, and further include a spring-engaging retainer positioned on each rod end and releasably held against a spring, such as by collets, such that the spring of each valve is compressed.

In one aspect of the present invention, a valve spring compressor includes a C-shaped frame defining opposing first and second jaws, the first jaw having a foot adapted to engage the retainer but adapted to move past the rod end. One of the first and second jaws has a power-assisted actuator thereon. The actuator has an extendable rod and has a manual control movable to a first position where the actuator moves the extendable rod to an intermediate retracted position for initial positioning of the valve spring compressor relative to the cylinder head. The manual control is further movable to a second position where the actuator moves the extendable rod to an extended position to both depress the retainer and compress the valve spring so that collets holding the retainer can be removed. The manual control is still further movable to a third position where the actuator moves the extendable rod to a retracted position that allows quick removal of the valve spring compressor from the valve and valve spring to another valve and valve spring on the cylinder head assembly. By this arrangement, the manual control can be manipulated to semi-automatically move the actuator to a selected one of the extended, retracted, and intermediate positions to facilitate repair of the cylinder head assembly.
In another aspect of the present invention, a valve spring compressor includes a C-shaped frame defining first and second jaws and includes an actuator for moving one of the first and second jaws relative to the other of the first and second jaws. The first jaw has an apertured foot adapted to engage the retainer but adapted to move past the rod end. The foot has a concave retainer-engaging surface that is adapted to stably nestingly engage the retainer despite a specific size of the retainer and valve spring being unknown ahead of time. The actuator is configured to selectively move the jaws to an expanded position for initial positioning of the frame relative to the cylinder head assembly, and to a clamped position for depressing the retainer and compressing the valve spring so that collets that hold the retainer can be removed.
In another aspect of the present invention, a valve spring compressor includes an adjustable C-shaped frame with first and second subframes defining opposing first and second jaws, respectively. An actuator is connected to the frame for moving the first and second jaws relative to each other, the first and second jaws being adapted to engage the retainer and the flared end of the valve. The second subframe slidably engages the first subframe. The C-shaped frame further includes a forger-operated trigger lock releasably engaging the first subframe to permit quick adjustment of the first subframe relative to the second subframe. The trigger lock provides a quick release for adjustment of a spacing between the first and second jaws and characteristically does not require loosening nor turning of a threaded member to effect the release.
These and other features, objects, and advantages of the present invention will become apparent to a person of ordinary skill upon reading the following description and claims together with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a perspective view of a spring valve compressor embodying the present invention;
Fig. lA is an exploded perspective view of the spring valve compressor shown in Fig. 1;
Fig. 2 is a side view of the spring valve compressor shown in Fig. 1;
Fig. 3 is a plan view of the retainer-engaging foot of the spring valve compressor taken in the direction III-III in Fig. 2;
Fig. 4 is a cross-sectional view taken along the line IV-IV in Fig. 3;
Fig. 5 is a side cross-sectional view of the pneumatic actuator and manual control, the manual control being shown schematically and in a centered position such that the extendable rod is biased to an intermediate position by the die spring in the actuator;
Figs. SA and SB are side cross-sectional views of the pneumatic actuator and manual control, the manual control being a spool valve and shown in the rod-extend and rod-retract positions;
Fig. 6 is a side view of the spool valve shown in Figs. SA and SB;
Fig. 7 is a side view of the valve spring compressor engaging a valve on a cylinder head;
Fig. 8 is a side view of the valve spring compressor including an extender for its foot, the compressor engaging a valve spring on a cylinder head;
Fig. 9 is a side view of the extender shown in Fig. lA;
Fig. 10 is an enlarged view of the opposing jaws and foot engaging a spring and spring retainer as shown in Fig. 7, the foot being about equal in size to the spring and spring retainer that it engages; and Fig. 11 is an enlarged view similar to Fig. 10, but showing a smaller size spring and spring retainer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
A valve spring compressor 30 (Fig. 1) embodying the present invention is provided for operably compressing a valve spring 20 (Fig. 7) in a cylinder head assembly 21 so that a selected valve 22 can be released and removed for repair. The illustrated cylinder head assembly 21 of Fig. 7 is exemplary of prior art cylinder head assemblies for internal combustion engines for passenger vehicles. In the illustrated assembly 21, the valve 22 has a flared end 23 and a rod end 24. The cylinder head assembly 21 further includes a cylinder head port 25 engaging the flared end 23 of the valve 22, a spring retainer 26 positioned on the rod end 24, and opposing collets 27 engaging a groove in the rod end 24. The spring retainer 26 captures the collets 27 and is held by the collets 27 against the spring 20 such that the spring 20 is compressed against the cylinder head casting 28.
The present valve spring compressor 30 (Fig. 1) includes a C-shaped frame 31 including first and second subframes 32 and 33, each having a jaw 34 and 35 thereon.
The jaw 35 has a foot 36 adapted to engage the spring retainer 26 (Fig. 7), but has an aperture 68 causing it to circumvent and slip past the rod end 24 such that collets 27 are released as the jaws 34 and 35 are moved together compressing the valve spring 20.
The foot 36 is particularly shaped to stably engage spring retainers having different diameters commonly encountered on cylinder head assemblies, as described below.
The subframes 32 and 33 are slidably interconnected for an initial gross adjustment, but are lockable in a selected position by a forger-operated trigger lock 38.
A pneumatically operated power actuator 40 is positioned on the subframe 32 for moving the jaw 35 between operative positions relative to foot 36.
Specifically, the actuator 40 has an extendable rod 41 and has a manual spool valve control 42 movable to a first position (Fig. 5) where the actuator 40 moves the extendable rod 41 to an intermediate position for initial fine positioning of the valve spring compressor 30 relative to the cylinder head assembly 21, to a second position (Fig. SA) where the actuator 40 moves the extendable rod 41 to an extended position to both depress the retainer 26 and compress the valve 22 so that the collets 27 can be removed, and to a third position (Fig. SB) where the actuator 40 moves the extendable rod 41 to an intermediate position that allows relatively quick positioning of the valve spring compressor 30 from the selected valve 22 and valve spring 20 to another valve and valve spring on the cylinder head assembly 21. Thus, the valve control 42 can be manipulated ._ to automatically move the actuator 40 to a selected one of the extended, retracted, and intermediate positions to facilitate repair of the cylinder head assembly 21.
The subframe 32 (Fig. lA) is L-shaped, and includes a long leg and a short leg.
The subframe 32 includes a pair of parallel L-shaped frame members 44 that are formed from sheet metal and rigidly connected together by spacers 45 with peened ends 46. The actuator 40 includes a housing 47 with a handle-forming section 48 that is shaped to mateably engage the short legs of the L-shaped frame members 44. The frame members 44 include holes 49, and screws 50 are extended through the holes 49 threadably into the handle-forming section 48 to secure the subframe 32 rigidly to the housing 47.
The housing 47 further includes a cylinder-forming section 51 that extends in a direction parallel a long leg of the subframe 32.
The subframe 33 (Fig. lA) includes a pair of parallel I-shaped frame members formed from sheet metal and fixedly secured together by transverse wall sections 54 and 55 at one end, and by the foot 36 at the other end. The transverse wall sections 54 and 55 combine with parallel frame members 53 to form an elongated channel 56. The channel 56 is shaped to telescopingly slidingly receive the long leg of the subframe 32, with the subframe 33 extending perpendicular to the long leg of the subframe 32 and with the frame members 53 engaging sides of the long leg for maximum strength in a direction toward the housing 47. The channel 56 closely engages the subframe 33 to control the perpendicularity of the subframes 32 and 33, but the channel 56 is sufficiently oversized such that abrasions on the subframe 32 will not cause it to bind within the channel 56. A pin 56' engages holes 56' ' in an end of the subframe 32 to prevent the subframe 33 from sliding completely off of subframe 32.
The outer transverse wall section 54 includes a tab 57 with a slot 58 therein, and the trigger lock 38 (Fig. lA) includes a ring-shaped section 59 having a first tab 60 shaped to pivotally engage the slot 58, with the ring-shaped section 59 extending around the long leg of the subframe 32 in-line with the channel 56. A second tab 61 extends from the ring-shaped section 59 opposite the first tab 60 and forms a trigger release handle that can be easily grasped. A tube 62 is attached to the inner wall section 55, and a spring 63 is positioned on the tube 62 along with a washer 63 ' . The spring 63 engages the second tab 61, causing the trigger lock 38 to move toward an angled locking position relative to the long leg of the subframe 32.

The ring-shaped section 59 includes a gripping edge 64 that bites into the long leg of the subframe 32 when in the locking position. The ring-shaped section 59 in combination with the spring 63 causes a bind between subframes 32 and 33, thus causing the subframe 33 to be held in a selected position. Notably, when the jaws 34 and 35 are biased apart (i. e. , when the actuator 40 is operated to extend rod 41), the ring-shaped section 59 of the trigger lock causes subframe 33 to bite into subframe 32 with force, thus holding the subframes 32 and 33 with increasing strength during use of the valve spring compressor 30. Contrastingly, the trigger lock 38 will let the subframe telescopingly adjust in direction A on subframe 32 with minimal pressure, even without purposefully releasing the trigger lock 38. The trigger lock 38 is relatively simple in its construction and is durable, such that it is low cost but very suitable for its purpose.
The trigger lock 38 can be easily tilted with finger pressure on second tab 61 to release it for adjusting the subframes 32 and 33.
The foot 36 (Figs. 2-4) is stamped or laser cut and then formed into a shaped component that includes a rectangular dished section 66 and a flat section 67.
The dished section 66 has a rectangular aperture 68 formed within its boundary, and the flat section 67 has a threaded hole 68' therein. The dished section 66 is arcuately formed in two orthogonal directions, such that the retainer-engaging recessed surface defines a shallow spherical section. This results in the comers 70-73 of the dished section 66 protruding a small distance. The dished shape of the dished section 66 is important to the ability of the foot 36 to universally stably engage spring retainers 26 of different sizes (see Figs. 10 and 11), because the shape causes the spring retainers 26 to tend to slide toward a centered stable position as they are depressed, regardless of whether the spring retainers 26 and valve spring 20 are larger or smaller than a width of depth of the foot 36. Based on testing, the optimal spherical radius 74 for the retainer-engaging surface is about 1.5 inches. The narrow width W of the dished section 66 is also important to the foot 36, because the foot 36 must be large enough to stably engage spring retainers 26 having relatively large diameters (Fig. 10), yet narrow enough to fit non-interferingly next to small-diameter spring retainers 26 that are closely positioned together without interferingly engaging the adjacent spring retainers 26 and valves 22 (Fig. 11). Based on testing, the optimal width is about 1.3 inches or slightly less.
Sometimes, a valve spring 20 and retainer 26 are positioned deep within a concavity in a cylinder head (see Fig. 8). In such case, a foot extender 75 is used. The foot extender 75 (Fig. lA) includes an abutment plate 76, a foot replicator section 77, and a extender sidewalls 78 that rigidly connect the abutment plate 76 to the foot replicator section 77. The extender sidewalls 78 include a section 80 that extends into mating engagement with the rectangular aperture 68. A hole 81 in the abutment plate 76 aligns with the threaded hole 68' in the foot 36, and a screw is extended through the hole 81 threadably into the hole 68' to secure the foot extender 75 to the foot 36. An end section 82 of the foot extender 75 can be formed to be identical to the dished section 66 or can have a customized shape intended to fit a particular cylinder head.
It is noted that the section 80 can be made to mateably frictionally engage the aperture 68 so that hole 81 is not needed.
The housing 47 of actuator 40 (Fig. lA) is a casting that includes the cylinder-forming section 51, the handle-forming section 48, and further includes an enlarged section 84 therebetween forming a part of the manual spool valve control 42.
The handle-forming section 48 forms a handle with the end of the first subframe 32 that is shaped for grasping by the palm and forgers of a repairman. The control 42 includes a spool 85 that is operably positioned in a bore in the enlarged section 84, and includes spaced-apart O-rings 85' that sealingly slidingly engage the bore. The spool 85 includes ends 86 and 87 that are positioned to be conveniently depressed by the repairman while holding the handle-forming section 48 for shuttling the spool 85 between its first, second, and intermediate third positions. A pipe nipple 88 extends from the enlarged section 84 through the handle-forming section 48 into the space between the frame members 44 of subframe 32. The pipe nipple 88 includes circular rings on a tapered snout that form a slip connect for an air supply hose. This arrangement positions the compressed air supply hose in a location where it does not become tangled with the valve spring compressor 30 during use. Further, it positions the compressed air supply hose and distributes a weight of the valve spring compressor 30 for optimal balance.
A piston 90 (Fig. lA) includes an extendable rod 91 and piston head 92 operably positioned in the cylinder formed by cylinder-forming section 51. A bearing 93 and end cap 94 close off an end of the cylinder, and a snap retainer 95 secures the end cap 94 in place. An O-ring 96 is positioned on the end cap 94 to maintain an air seal. A
polymeric end piece 97 is attached to an end of the extendable rod 91, such as by a screw 97 ' . The end surface of the end piece 97 is rounded to promote a more secure abutting engagement with the flared end 23 of the valve 22. Also, the polymeric _7_ material is durable but is made of a material such as nylon that reduces the likelihood of damagingly engaging the cylinder head assembly 21, which is important because many modern cylinder heads are made of aluminum which is susceptible to damage from hard objects.
The cylinder of the cylinder-forming section 51 (Fig. 5) includes a large diameter section where the piston head 92 operates, and further includes a small diameter section.
A piston spring 99 and stopper 100 are positioned in the small diameter section of the cylinder-forming section 51 and are secured therein by a snap ring 101. The piston spring 99 is configured to bias the piston 90 from its fully retracted position (Fig. SB) to an intermediate position (Fig. 5) when the compressed air is vented at both ends of the spool 85. This positions the extendable rod 91 generally closer to a valve 22, such that it is easier to position the valve spring compressor 30 for use on an adjacent valve, but allows a repairman to manipulate the valve spring compressor 30 including pressing the extendable rod 91 against a flared end 23 of a valve 22 to achieve an increased space between jaws 34 and 35. It is noted that the jaws 34 and 35 include at least the foot 36 and the end piece 97, respectively, and further include a portion of their respective supporting structures on subframes 32 and 33.
The spool 85 is positionable in a centered position (Fig. 5) so that the compressed air is dead-headed by the O-rings 85' on the spool 85, and so that the air chambers 102 and 103 on the opposing sides of the piston head 92 are vented to atmosphere through air passageways 104 and 105, respectively, in the housing 47. The spool 85 further is positionable in a second position for extending the piston 90 (Fig. SA), where the air chamber 102 is vented, but where compressed air is routed through the pipe nipple 88 into a center portion 106 of the enlarged section 84, and is further directed through the air passageway 105 to the air chamber 103 by the spool 85. This causes the piston 90 (and extendable rod 91) to move to the extended position, such that the jaws 34 and 35 are brought together to compress the valve spring 20. The spool 85 further is positionable in a third position for retracting the piston 90 (Fig. SB), where the air chamber 103 is vented, but where the compressed air is routed through the pipe nipple 88 into the center portion 106 of the enlarged section 84, and is further directed through the air passageway 104 to the air chamber 102 by the spool 85. It is noted that the depression 108 in the spool 85 for receiving the O-rings 85' (Fig. 6) is rounded on an _g_ outer side surface 109 to help retain the O-ring 85 ' in place as the spool 85 is shifted back and forth in the bore of the enlarged section 84.
To operate valve spring compressor 30, the cylinder head assembly 21 is positioned on a holder so that the top side (i. e. , that part including the valve springs 20) is accessible, as well as the bottom side (i. e. , that part including the flared ends of the valves). The valve spring compressor 30 is manipulated into position on the cylinder head assembly 21, including grossly adjusting the spacing between the jaws 34 and 35 by pressing on trigger lock 38 and slidingly adjusting the subframes 32 and 33 so that the jaw 34 abuts the flared end 23 of the selected valve 22 and so that the jaw 35 is positioned fight to retainer 26. The spool 85 is then moved to the position where the extendable rod 91 is extended by operation of the compressed air. As the extendable rod 91 moves, the foot 36 is moved so the rod end 24 slides into the aperture 68.
The retainer 26 centers itself and stabilizes in the dished section 66 of foot 36.
As the valve spring 20 is compressed, the collets 27 move out of the inner portion of the retainer 26 that captures them, and the collets 27 are released. After the collets 27 are removed, the retainer 26 can be taken off the end of the rod end 24 by retracting the rod 41 so that the valve spring 20 is released. The valve 22 can now be removed and refurbished, or replaced. To reinstall the valve 22, the operation is reversed.
In the foregoing description, persons skilled in the art will recognize that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.

Claims (23)

1. A valve spring compressor for compressing a valve spring in a cylinder head assembly so that a selected valve can be released and removed for repair, the cylinder head assembly including a cylinder head engaging a port-sealing flared end of the valve, and a spring-engaging retainer positioned on a rod end of the valve that is releasably held against the spring such that the spring is compressed against the cylinder head, comprising:
a C-shaped frame defining opposing first and second jaws, the first jaw having a foot adapted to engage the retainer but adapted to move past the rod end, one of the first and second jaws having a power-assisted actuator thereon for moving one of the first and second jaws relative to the other of the first and second jaws, the actuator having an extendable rod and having a manual control movable to a first position where the actuator moves the extendable rod to an intermediate position for initial positioning of the valve spring compressor relative to the cylinder head, and movable to a second position where the actuator moves the extendable rod to an extended position to both depress the retainer and compress the valve spring so that collets that hold the retainer can be removed, and movable to a third position where the actuator moves the extendable rod to in a retracted position that allows relatively quick removing of the valve spring compressor from the valve and valve spring to another valve and valve spring on the cylinder head assembly, whereby the manual control can be manipulated to semi-automatically move the actuator to a selected one of the extended, retracted, and intermediate positions to facilitate repair of the cylinder head assembly.

2. The valve spring compressor defined in claim 1, wherein the actuator includes a hose connector adapted for connection to a source of compressed air, the hose connector extending at least partially within a portion of the frame.

3. The valve spring compressor defined in claim 2, wherein the actuator includes a housing integrated into the frame and forming a handle thereon, and includes a spool operably positioned in the housing.

4. The valve spring compressor defined in claim 3, wherein the spool is a three-position spool and defines the first, second, and third positions.

5. The valve spring compressor defined in claim 4, wherein the actuator includes a piston connected to the extendable rod, and includes a spring located in the housing that biases the piston to the intermediate position.

6. The valve spring compressor defined in claim 1, wherein the extendable rod is manually movable when in the intermediate position.

7. The valve spring compressor defined in claim 6, including a spring biasing the rod from the retracted position to the intermediate position.

8. The valve spring compressor defined in claim 1, wherein the C-shaped frame includes first and second subframes that are adjustably engaged with each other characteristically without the use of separate threaded fasteners.

9. The valve spring compressor defined in claim 8, including a trigger lock operably attached to the first and second subframes, the trigger lock including a finger release movable to an unlocked position for releasing the first and second subframes for adjustment but that is biased toward a locked position where the subframes are fixed to each other.

10. The valve spring compressor defined in claim 1, wherein the foot has a retainer-engaging surface that is concavely dished and two-dimensionally arcuate in shape.

11. The valve spring compressor defined in claim 1, including an extender configured to mateably engage and be attached to the foot, and having a surface shaped to stably engage a retainer.

12. The valve spring compressor defined in claim 1, wherein the extendable rod includes a plastic end that resists moving and damaging the valve.

13. The valve spring compressor defined in claim 12, wherein the plastic end includes a convex surface shaped to securely engage and locate on the selected valve.

14. A valve spring compressor for compressing a valve spring in a cylinder head assembly so that a valve can be released and removed for repair, the cylinder head assembly including a cylinder head engaging a port-sealing flared end of the valve, a spring-engaging retainer positioned on a rod end of the valve, and a spring-engaging retainer positioned on the rod end and releasably held against the spring such that the spring is compressed against the cylinder head, comprising:
a C-shaped frame defining first and second jaws and including an actuator for moving the first and second jaws relative to each other, the first jaw having an apertured foot adapted to engage the retainer but adapted to move past the rod end, the foot having a concave retainer-engaging surface that is adapted to stably nestingly engage the retainer despite a specific size of the retainer and valve spring being unknown ahead of time, the actuator being configured to selectively move the jaws to an expanded position for initial positioning of the frame relative to the cylinder head assembly, and to a clamped position for depressing the retainer and compressing the valve spring so that collets holding the retainer can be removed.

15. The valve spring compressor defined in claim 14, wherein the foot is rectangular in shape and is adapted to engage retainers that are larger than its width.

16. The valve spring compressor defined in claim 15, wherein the retainer-engaging surface is non-uniformly shaped in orthogonal directions, and includes corners that protrude a small amount from a remainder of the retainer-engaging surface.

17. The valve spring compressor defined in claim 16, wherein the foot includes an aperture that is rectangularly shaped.

18. The valve spring compressor defined in claim 17, wherein a size of rectangular aperture is less than a largest valve spring that the foot is adapted to engage.

19. The valve spring compressor defined in claim 14, wherein the retainer-engaging surface is arcuately shaped in orthogonal directions, and includes corners that protrude from a remainder of the retainer-engaging surface.

20. A valve spring compressor for compressing a valve spring in a cylinder head assembly so that a valve can be released and removed for repair, the cylinder head assembly including a cylinder head engaging a port-sealing flared end of the valve, and a spring-engaging retainer positioned on a rod end of the valve and releasably held against the spring such that the spring is compressed against the cylinder head, comprising:
an adjustable C-shaped frame including first and second subframes defining opposing first and second jaws, respectively, and an actuator connected to the frame for moving the first and second jaws relative to each other, the first and second jaws being adapted to engage the retainer and the flared end of the valve, the second subframe slidably engaging the first subframe, and including a finger-operated trigger lock releasably engaging the first subframe to permit quick adjustment of the first subframe relative to the second subframe, the trigger lock providing a quick release for adjustment of a spacing between the first and second jaws and characteristically not requiring loosening nor turning of a threaded member to effect the release.

21. The valve spring compressor defined in claim 20, wherein the trigger lock is pivoted to one of the first and second subframes and is movable to a release position but is biased to a locked position, and includes material that fractionally engages and bends against the other of the first and second subframes when in the locked position.

22. The valve spring compressor defined in claim 21, wherein the trigger lock includes a tab that fits into an opening on the one subframe to form a pivot for the trigger lock, and further includes a spring spaced from the tab that biases the trigger lock into an angled binding condition with respect to the other of the subframes.

23. The valve spring compressor defined in claim 21, wherein the first subframe includes frame members defining a channel, and the second subframe includes a section that telescopingly engages the channel.