GB2161741A - Valve spring compressor tools for poppet valves - Google Patents

Abstract

A tool (10) for compressing the springs of poppet valves in e.g. i.c. engine cylinder heads comprises a base (11), a frame (12), a slide rail (17) extending horizontally across the frame, a carrier sleeve (24) slidable 12 along the rail (17) and a spring-compressing lever (25) hinged 13 (at 26) to the carrier sleeve (24). The lever (25) can be swung down to engage and compress a selected valve spring in a cylinder head supported on the base (11), over which valve the lever has been positioned by sliding the sleeve (24) along the rail (17). Thus the reaction to the spring-compressing downward thrusts of the lever (25) is transmitted through the carrier sleeve (24), rail (17), and frame (12) to the base (11). The rail (17) is vertically-adjustable by sliding in slots (16) in the frame uprights (13), pegs (20) fitted into selected holes (18) in the uprights locating the rail at the selected height. A range of adaptor plates (37) is provided for the base (11) each plate (37) having a set of bosses (38) to support the heads of the poppet valves of a particular design of cylinder head. <IMAGE>

Description

SPECIFICATION Valve spring compressor tools for poppet valves This invention relates to tools for compressing the valve springs of poppet valves.

Whilst the invention is applicable primarily to poppet valves in the cylinder heads of i.c. engines, it may be applied with advantage also to poppet valves mounted in other kinds of detachable or portable valve blocks affording a valve seating for the or each poppet valve mounted therein. However, the principal field of interest is that of i.c. engine cylinder heads and the invention will accordingly be described in relation to such cylinder heads; but it is to be understood that the term "cylinder head" as used in the following specification and claims is to be of interpreted as including all such other valve blocks, wherever appropriate in the context.

A poppet valve in an i.c. engine cylinder head is provided with a powerful helical compression spring surrounding its stem and acting between a seating on the cylinder block and a collar secured on the valve stem by means of a pair of collets, or the like, the valve spring being mounted in the precompressed state and biassing the valve head onto its seating to tend to close the valve and hold it closed. When it is desired to remove the valve member for maintenance or replacement purposes, it is necessary first to compress the valve spring further against its seating, so as to relieve the spring pressure acting on the valve stem and to allow the spring collar to be slid clear of the securing collets on the valve stem so that the valve spring and valve can be removed from the head.

The spring must be similarly compressed during the fitting of a replacement or service poppet member in the cylinder head.

Such disassembly of the poppet valve of an engine is a not-infrequent requirement in a workshop dealing with the maintenance of i.c. engines, although it is required less frequently nowadays than in former years as a result of the major improvements that have been made in fuels, lubricants and manufacturing quality control. The disassembly is normally performed with the cylinder head removed from the cylinder block so as to allow the removal of the valve members from the combustion chambers.

A variety of different tools has been provided in the past for compressing poppet valve springs prior to the removal or replacement of the valves.

Some of these have been of screw type broadly comprising a frame which is suitably engaged with the cylinder head to overlie the valve guide passage, and a screw plunger threaded in the frame and having an annular head designed to bear against the spring retaining collar, and to depress the collar and compress the spring when the plunger is screwed down. Others of such tools have employed a lever pivoted in a frame which is suitably engaged with the cylinder head so as to provide a fulcrum for the lever enabling it to be fitted over the valve stem and swing down to bear on the collar and compress the valve spring.

A feature of all these known tools is that they have to be appropriately engaged with the cylinder head so as to provide the necessary reaction for the thrust imposed by the lever or screw plunger in compressing the valve spring. Moreover, tools of known type have to be disengaged from the head after one valve spring in a multi-valve cylinder head has been compressed and released from or refitted to its valve stem, and then re-engaged with the cylinder head in a different relative position before the spring of the next succeeding valve can be compressed. It has also become the practice for different automobile or engine manufacturers and specialist servicing tool manufacturers to produce different designs of valve spring compressor tool which are specific to different particular designs of cylinder head.As a result, a typical engine maintenance workshop will have to keep a very considerable number of different valve spring compressor tools so that they will be able to deal with all the different makes of engine which commonly come to them for attention.

From one aspect, the present invention provides a tool for compressing poppet valve springs that can be readily adapted for use in conjunction with a wide variety of cylinder heads of different designs.

In one form of the invention, the tool comprises a base on which a cylinder head can be positioned and supported, and a spring-compressing member movable relative to the base for engaging and compressing a valve spring of a poppet valve mounted in the cylinder head when so supported, the said member being connected to the base in such a manner that the reaction to a spring-compressing thrust on the said member is transmitted through the said connection to the base, instead of being derived from the engagement of the tool with the cylinder head. Thus it is not necessary to provide different tools respectively adapted to be operatively engaged with individual designs of cylinder head.Provided that a measure of adjustability of the connection between the movable springcompressing member and the base is provided to accommodate heads of different heights or different shapes, a single tool embodying the invention can be employed in connection with several different cylinder head designs.

From another aspect, the present invention comprises a tool for compressing poppet valve springs in a multi-valve cylinder head, in which the springcompressing member of the tool can be moved from one operative position to another without repositioning the tool as a whole relative to the cylinder head.

Thus in one form of the invention from this aspect, the tool comprises a base on which a cylinder head with a plurality of poppet valves can be positioned and supported, and a member referred to as the spring-compressing member, which is movable relative to the base through a compression stroke for compressing a valve spring of the cylinder head when so supported, means being provided for traversing the spring-compressing member rel ative to the base to move it into successive operating positions in each of which it is operable to compress the spring of one of the several poppet valves in the head, without repositioning movement of the head relative to the base between successive spring-compressing operations.

From yet another aspect, the invention comprises a tool for compressing poppet valve springs, comprising a base on which a cylinder head can be positioned and supported and a lever pivotally connected to the base, or to structure mounted on the base, in a position in which it can be swung about a pivotal axis to engage and compress a valve spring of a poppet valve mounted in the cylinder head when so positioned and supported on the base. In a preferred form of the invention from this latter aspect, the lever is hinged adjacent one end to a carrier member slidably attached to a rail fixed to be base, the lever extending from the rail above and over the base and being traversable along the rail, by the sliding of the carrier member along the rail, to move the lever relative to the base into successive operating positions.In each successive operating position the lever can be swung down, e.g. manually, by pivotal movement about the hinge axis, to engage and compress the spring of a successive one of the several poppet valves of a multi-valve cylinder head supported on the base, so that the springs of several or all of the valves in the head can be compressed in sequence without the need to reposition the head between successive spring-compressing operations.

Preferably the height of the rail relative to the base is adjustable, for accommodating cylinder heads of different heights or shapes. For example, opposite ends of the rail may be slidably mounted in tracks formed in a pair of uprights rigidly secured to the base, and means such as locating pins engaged in selected vertically-spaced holes in the uprights may be provided for locating the rail at different selected heights, in each of which it supports the carrier as a fulcrum for the lever operation.

The spring-compressing lever itself may include a portion adapted to engage the spring retaining collar of a poppet valve on both sides of the valve stem, for depressing the collar by angular movement of the lever towards the base.

However, at least one extension fitting may be provided, which is adapted to be positioned beneath the said portion of the lever for engaging the spring retaining collar of a valve to transmit a spring-compressing thrust of the lever thereto.

The base may be provided with at least one adaptor plate adapted to be placed in a located position on the base for supporting a cylinder head on the adaptor plate, the adaptor plate being provided with one or more upwardly-projecting bosses each arranged to lie within a combustion chamber of the head and to support the head of one of the poppet valves during the compression of the valve spring of that valve by the tool.

The invention may be carried into practice in various ways, but one specific embodiment thereof will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a valve spring compressor tool for poppet valves; Figure 2 is a rear elevation of the tool of Figure 1; and Figure 3 is a sectional elevation on the line Ill-Ill in Figure 1, showing the tool with a cylinder head positioned on its base.

The tool 10 shown in the drawings comprises a rectangular base II provided with bolt holes (not shown) to enable it to be bolted semi-permanently to a bench, if so required, and a rectangular frame 12 mounted on the base along its rear edge. The frame 12 comprises two uprights 13, a top crossmember 14 and a bottom cross-member 15, rigidly welded together, the frame being welded to the base 11 so as to extend perpendicularly thereto.

The two uprights 13 are of rectangular-section tubular form, and each is formed in its inwardly-facing side wall with a longitudinal slot 16 which receives one end of a rigid vertically-adjustable support rail 17 of flat strip form. Each upright 13 is also formed in each of its forward-facing and rearfacing side walls with a series of spaced holes 18, the holes in the front wall being in register with the holes in the rear wall so that a locating peg 20 can be passed through a selected pair of registering front and rear holes in each upright 13.The opposite ends of the adjustable support rail 17 can slide in the respective slots 16, and the support rail 17 is drawn vertically upwardly against the undersides of the two locating pegs 20 in the two uprights 13 by means of a pair of tension springs 22 each secured at one end to a lug 23 depending from the top cross-member 14 and at the other end in a hole 24 in the support rail 17.

A flattened rectangular-section slide collar 24 is slidably mounted on the support rail 17, and a lever arm 25 is hinged at 26 adjacent one end 27 to the slide collar 24. The main length of the lever arm 25 extends forwardly over the base 11, and the lever arm is biassed in the upward angular direction about its hinge 26 by means of return springs 28 acting between the rear end 27 of the lever arm and lugs 29 on the slide collar 24. The lever arm 25 is a rigid member formed by a pair of horizontally-spaced metal strips 31,32 joined by a yoke 33 at their forward ends and by the hinge pin 26 adjacent the rear ends 27. A handle 35 is mounted on the yoke 33 at the forward end of the lever.

An adaptor plate 37, one of a series of such plates, is removably positioned on the base 11 and located thereon by locating means not shown, such as a fitting recess in the base 11. The particular adaptor plate 37 shown has a series of four upwardly-projecting elongate bosses 38 corresponding in position to the four combustion chambers of a particular i.c. engine cylinder head 39 shown positioned and supported on the adaptor plate 37 in Figure 3. The purpose of the bosses 38 is to provide firm support for the heads 40 of the poppet valves 41 in the various combustion chambers of the cylinder head whilst their valve springs 42 are being compressed by the lever arm 25. The bosses 38 may also serve to locate the cylinder head 39 on the adaptor plate 37, or additional locating means (not shown) for the head 39 may be provided on the plate 37.There will be a series of such adaptor plates, each provided with suitably positioned bosses and/or optionally with other locating means appropriate to a respective one of a range of different cylinder heads with which the tool will be required to be used.

To use the tool, a cylinder head 39 is correctly positioned on its matching adaptor plate 37 resting on the base 11, with the posses 38 projecting within the combustion chambers beneath the heads 40 of the valves 41. The support rail 17 is adjusted to a suitable height, simply by inserting the two pegs 20 above the rail 17 in appropriate holes 18 in the two uprights 13 and allowing the springs 22 to draw the rail 17 upwards against the under sides of the pegs 20. With the lever arm 25 supported in its raised position (shown in chain lines in Figure 3) by the return springs 28, the slide collar 24 together with the lever arm 25 is then slid along the support rail 17 into a position in which the lever arm 25 overlies the first valve 41 to be dismantled with the valve stem 43 centralised beneath and between the two strips 31,32 of the divided arm 25.The lever arm 25 can then be swung down manually, pivoting about the hinge 26, until the two strips 31,32 (or a suitable fitting mounted on the lever arm below them) bear on the valve spring retaining collar 44, one on either side of the valve stem 45. Further manual depression of the lever arm 25 then compresses the valve spring 42, the valve head 40 being supported on the boss 38, until the valve collets 46 can be removed. The lever arm 25 can then be swung up again about its hinge 26 allowing the valve spring 42 to relax and extend, and finally the spring 42 and its collar 44 can be removed leaving the valve 41 resting on the boss 38.The slide collar 24 and the lever 25 are then slid along the support rail 17 until the lever 25 overlies the next valve in the head to be removed, when the operation of compressing the spring and removing the collets, and then raising the lever and removing the valve spring, is again performed.

The cycle is repeated for each valve in turn whose spring is to be removed, the lever 25 and slide collar 24 being simply slid along the support rail 27 from one valve position to the next whilst the cylinder head 39 remains correctly positioned on its adaptor plate 37 on the base 11 throughout. The reaction to the spring-compressing thrust applied to the lever arm 25 is transmitted through the hinge 26, the rail 17 and the frame 12 to the base 11 on which the cylinder head rests, rather than being derived from the engagement of a lever fulcrum member with the cylinder head itself.

It will be appreciated that when the lever arm 25 has been depressed to comprises a valve spring it is necessary to be able to reach and remove the collets from the valve stem while the spring remains held compressed. The divided form of the lever arm allows for this, and in some cases the two side strips of the arm can bear directly down on the spring collar to compress the spring. This ensures that the load is applied evenly and axiallysymmetrically to the spring on both sides of the valve stem which projects up between the two side strips of the divided portion of the lever arm.

However, for use with cylinder heads whose valve stems and springs are housed in recesses in the top of the head or are otherwise inaccessible, a series of different fittings and attachment, e.g. of annular or tubular form, may be provided for attachment to the under side of the lever arm to fit over a valve stem and bear on the spring retaining collar in its recess in the cylinder head, allowing the spring to be compressed by depression of the lever 25. An appropriately shaped fitting of suitable size would be selected for attachment to the arm to suit a particular shape of cylinder head.

The top cross-member 14 of the frame 12 is forwardly and downwardly inclined and is provided with a series of numbered holes 48 to receive the stems of the valves themselves, thus providing temporary storage for the valves when they have been removed from the head and ensuring that they can be identified for re-assembly in their original sequence in the head without difficulty.

The spring compressor tool described and illustrated is thus capable of receiving and accommodating a range of many different designs of cylinder head for valve removal, and of being rapidly and easily adjusted to suit individual heads.

The vertical adjustability of the support rail 17 lends itself to rapid adjustment to the height of a particular head, the arrangement of pegs 20, holes 18 and lifting springs 22 being particularly convenient although there are of course many other different possible ways of providing for the vertical adjustment of the level of the lever hinge 26. The tool can be used quickly and easily to remove the valve springs of a complete set of valves in a cylinder head one by one, simply by sliding the lever arm along the rail 17 from valve to valve without any need to reposition the read relative to the tool as a whole.

Whilst it is convenient to provide a series of different adaptor plates 37 with differently- located and/or differently dimensioned bosses 38 to suit the number and positions of the combustion chambers in the range of cylinder heads to be handled, it is of course also perfectly possible to dispense with the use of integral bosses 38 on the plates 37 and to use instead a plain flat adaptor plate, or even to rest a cylinder head directly on the base 11, and to support the valve heads 40 on separate packing pieces resting on the plate or base in the combustion chambers.

Claims (14)

1. A tool for compressing poppet valve springs, which comprises a base on which a cylinder head (as hereinbefore defined) can be supported and a member, referred to as the spring-compressing member, which is movable relative to the base for engaging and compressing a valve spring of a poppet valve mounted in the cylinder head when supported on the base, the spring-compressing member being connected to the base in such a manner that the reaction to a spring-compressing thrust on the said member is transmitted through the said connection to the base.

2. A tool for compressing poppet valve springs, which comprises a base on which a cylinder head (as hereinbefore defined) can be positioned and supported, and a lever pivotally connected to the base, or to structure mounted on the base, in a position in which it can be swung about a pivotal axis to engage and compress a valve spring of a poppet valve mounted in the cylinder head when so positioned and supported on the base.

3. A tool for compressing poppet valve springs, which comprises a base on which a cylinder head (as hereinbefore defined) with a plurality of poppet valves can be positioned and supported, and a member, referred to as the spring-compressing member, which is movable relative to the base through a compression stroke for compressing valve spring of the cylinder head when so supported, means being provided for traversing the spring- compressing member relative to the base to move it into successive operating positions in each of which is it operable to compress the spring of one of the several poppet valves in the head, without repositioning movement of the head relative to the base between successive spring-compressing operations.

4. A tool as claimed in Claim 2, in which the lever is hinged adjacent one end to a carrier member slidably attached to a rail fixed to the base, the lever extending from the rail above and over the base and being traversable along the rail, by the sliding of the carrier member along the rail, to move the lever relative to the base into successive operating positions.

5. A tool as claimed in Claim 4, in which the lever is spring-biassed in the return angular direction about its hinge axis.

6. A tool as claimed in Claim 4 or Claim 5, in which the height of the rail relative to the base is adjustable.

7. A tool as claimed in Claim 6, in which opposite ends of the rail are slidably mounted in tracks formed in a pair of uprights rigidly secured to and protruding upwardly from the base, means being provided for locating the rail at different selected heights in each of which it supports the carrier as a fulcrum for the lever operation.

8. A tool as claimed in Claim 7, in which the said means for holding the rail comprises a pair of pegs respective insertable into selected holes of a pair of rnws of vertically-spaced holes formed one in each of the respective uprights.

9. A tool as claimed in Claim 7, in which opposite ends of the rail are arranged to underlie the respective pegs and are upwardly spring-biassed there-against by spring means acting between the rail and the uprights.

10. A tool as claimed in any one of Claims 7 to 9, in which the uprights form part of a frame structure mounted on the base, the frame structure including an upper cross-member formed with a series of spaced holes to receive the stems of detached poppet valves for temporarily supporting and storing the valves.

11. A tool as claimed in any one of Claim 2 and 4 to 10, in which the lever includes a portion adapted to engage the spring retaining collar ofa poppet valve on both sides of the valve stem, for depressing the collar by angular movement of the lever towards the base.

12. Atool as claimed in Claim 11, in which the said collar-engaging portion of the lever comprises two laterally-spaced beams which extend longitudinally of the lever and can respectively engage the spring collar one on either side of a valve stem protruding upwardly between them.

13. A tool as claim in Claim 11 or Claim 12, including at least one extension fitting adapted to be positioned beneath the said portion of the lever for engaging the spring retaining collar of a poppet valve to transmit a spring- compressing thrust of the lever thereto.

14. A tool as claimed in any one of the preceding claims, in which the base is provided with at least one adaptor plate adapted to be placed in a located position on the base for supporting a cylinder head on the adaptor plate, the adaptor plate being provided with one or more upwardly-projecting bosses each arranged to lie within a combustion chamber of the head and to support the head of one of the poppet valves during the compres sion of the valve spring of that valve by the tool.

'its. A tool for compressing poppet valve springs, substantially as specifically described herein with reference to the accompanying drawings.