A DEVICE FOR COMPRESSING THE COMPRESSION SPRINGS OF DISK VALVES IN MOTOR CYLINDER HEADS

Abstract: A device for compressing the compression spring of disk valves in motor cylinder heads comprises a C-shaped arch part (4) with an abutment (6) and a movable pressing means (5). Further, the device comprises a stand (1) with on one hand a carrier (2) for the cylinder head, and on the other hand a guide (7) along which a holder (9) is reciprocally movable, with which holder the arch part (4) is connected via at least two vertically separated, thin and wide spring leaves (12, 12'), which on one hand are flexible upwards and downwards due to their small thickness, in order to enable a movement of the arch part between different vertical positions, and on the other hand are rigid laterally due to their width, in order to prevent the arch part from skewing laterally relative to the holder.

Description: A DEVICE FOR COMPRESSING THE COMPRESSION SPRINGS OF DISK VALVES IN MOTOR CYLINDER HEADS Technical Field of the Invention This invention relates to a device for compressing the compression springs of disk valves in motor cylinder heads comprising a C- shaped arch part with an abutment at a first free end and a pressing means located at a second end, which pressing means is reciprocally movable by means of a force pro- ducer. Prior Art Cylinder heads for internal combustion engines comprise a number of valves which are placed after each other in rows, each individual valve comprising a disk, a rod and a compression spring. The disk cooperates with a seat in a cavity in the bottom side of the head, said cavity opening into an appurtenant cylinder. In turn, the spring is placed in a cavity that opens into the top side of the head and is locked relative to the valve rod by means of a ring-shaped, dismountable locking means. In modern engines, this upper cavity is in most cases very deep, wherefore both the spring and the locking means are located at a considerable distance from the top side of the head. It should also be mentioned that the spring is very strong, in order to close the disk reliably against the valve seat in connection with each compression phase in the cylinder. In order to compress the spring in connection with the assembly of the valve in the cylinder head, as well as the disassembly of the same in connection with engine reconditioning, special arrangements of two main categories have been previously used, viz . on one hand simpler hand tools and on the other hand sophisticated machine equipment. A commonly occurring hand tool consists of a substantially Oshaped arch part which at a first free end has an abutment and at the opposed other end comprises a pressing means that is reciprocally movable by means of some form of force producer. In practice, this force producer may consist of a conventional, manually rotatable screw, or alternatively, a pneumatic piston-cylinder mechanism. Such hand tools are per se rather cheap and due to this, they are available also in small garages. However, they are troublesome to handle, not only in connection with the handling of the individual valve, but also in connection with the movement from one valve to the other. In practice, this involves that the total time for the assembly and disassembly, respectively, of all valves contained in a cylinder head, becomes relatively long. In connection with engine reconditio- nings, this implies that the cost for the reconditioning work becomes comparatively high. The handling of the tool becomes particularly complex, specifically in connection with modern cylinder heads, in that here the upper cavities for the springs are very deep. Thus, the pressing means that are related to previously known hand tools are relatively ungainly and difficult to bring into a correct engagement with the locking means . Previously known machine equipments of a more sophisticated type are usually based on the use of powerful, pneumatic piston-rod mechanisms that are mounted in a column of a stand, in which is comprised an adjustable table, on which the cylinder head can be put in a determined, desired position in relation to the stand. In such cases, one or several valve rows are oriented substantially parallel to a guide, along which the pressing means working pneumatically is reciprocally movable. This involves that the movement of the pressing means between different valves, and the application of the pressing means, may be performed in a simple and time-saving manner. However, equipments of this type are technically comparatively complicated and, thereby, expensive. This implies that only bigger garages and motor works, which frequently work with engine reconditionings , can afford to invest in an equipment well adapted to its purpose. Only to a limited extent it occurs that small workshops possess such equipment. Another inconvenience of expensive machine equipment is that the function of the pressing means is entirely dependent on the availability of a plant for compressed air. Objects and Features of the Invention The present invention aims at eliminating the above mentioned inconveniences of previously known hand tools and machine equipements, respectively, and providing an improved spring compressing device. Thus, a primary object of the invention is to provide a device that on one hand works in a smooth and efficient way in connection with the handling of individual valves, as well as the movement between these, and on the other hand is constructively simple, in order to permit manufacturing at low cost. In other terms, the device shall combine the advantages of previously known hand tools and machine equipments, respectively, without, for this sake, the disadvantages of those being inherent in them. Therefore, a ultimate object of the device according to the invention is that it shall be possible to purchase and be at the disposal of not only larger workshops, but also of small workshops. In accordance with the invention, at least the primary object is attained by the features defined in the characterizing clause of claim 1. Furthermore, preferred embodiments of the invention are defined in the dependent claims. Brief Description of the Appended Drawings In the drawings : Fig 1 is a perspective view of the device according to the invention, Fig 2 is a side view of the same device shown together with a cylinder head, a pressing means included in the device being shown distanced from a valve and the spring of the latter, Fig 3 is a side view corresponding to Fig 2, showing the pressing means in an active state in contact with the valve spring, Fig 4 is an enlarged detail section showing the pressing means in connection with a compression of a valve spring in the active state according to Fig 3, Fig 5 is a corresponding detail section showing the pressing means in the inactive state according to Fig 2, Fig 6 is a front view of the device according to the invention illustrating how the pressing means may be inclined relative to a carrier for a cylinder head, Fig 7 is a side view showing how the pressing means may be moved depthways relative to the carrier, and Fig 8 is a perspective view illustrating a detail of the device . Detailed Description of a Preferred Embodiment of the invention In Fig 1, reference numeral 1 generally designates a stand 1 that may be placed on a table and that comprises a carrier designated by reference numeral 2, for receiving a cylinder head. Such a cylinder head is schematically shown in Fig 2 and 3, where it is designated 3. Moreover, in the device is included a substantially C-shaped arch part designated 4 in its entirety, to which is connected a pressing means 5. More specifically, the pressing means is joined to the upper, free end of the arch part, while the lower free end of the arch part comprises an abutment 6 in the form of a vertically directed, partly tapering tap. In the stand is included a guide in the form of a rod-shaped or tubular element 7, under which is provided a rule 8 with a polygonal cross-section, e.g., in the shape of a square box profile. A holder, which in its entirety is designa- ted 9, is reciprocally movable along the guide 7 and comprises on one hand a runner 10 and on the other hand a post 11. According to a feature that is characteristic for the invention, the C-shaped arch part 4 is connected with the holder 9, more specifically with its post 11, via at least two thin and wide spring leaves 12, 12'. In practice, these leaves 12, 12' may be made of spring steel, although other materials are also feasible. The arch part 4 comprises a substantially straight, vertically oriented middle portion 13. The upper elongated spring leaf 12 is connected with the arch part by an outer end, in the region of the upper part of the middle portion 13, while the lower spring leaf 12 ' is connected with the arch part by its outer end, in the region of the lower end of the middle portion. The interior or rear ends of the spring leaves are con- nected with upper and lower ends, respectively, of the post 11. In practice, the connection of the spring leaves with the arch part and the post, respectively, is realized by two separate screws 14 or similar, at each end. The post 11 is co-rotatively connected with one end of a shaft 15, which extends transversely to the guide element 7, in particular perpendicularly to the latter. The opposed end of the shaft 15 bears against the back of the middle portion 13. More specifically, the outer end of the shaft 15 is inserted into a vertical groove 40 that is recessed in the back of the middle portion 13 and may have a depth of about 5 mm. At the top and at the bottom, this groove is delimited by semi-circularly shaped stop surfaces 41, 41', between which extend straight steering surfaces 42, 42'. In practice, this groove may have a length within the range of 50 to 100 mm (e.g., 60 mm) and a width that barely exceeds the diameter of the shaft 15 (which may be 20 mm) . Therefore, the arch part is vertically adjustable relative to the shaft 15, more specifically between the stop surfaces 41, 41'. The width extension of the spring leaves 12, 12' is horizontally oriented and by their small thickness, the leaves are smootly flexible, upwards as well as downwards. This implies that the arch part is movable vertically without any difficulty, the middle portion of the arch part always being held substantially parallel to the post 11, independently of the adjusted height position. On the other hand, by their width the spring leaves are laterally rigid; something that prevents the arch part from skewing relative to the post 11. In other terms, the spring leaves guarantee that the arch part 4 and the post always are kept in a common plane. The shaft 15 is led through a through-hole in the upper portion of the runner 10, that protrudes from a sleeve 16 which encircles the guide element 7. Advantageously, this sleeve comprises a linear bearing in order to enhance the movement of the runner along the guide element . In connection with said hole, there is a clamping mechanism 17, by means of which the shaft may be fixed in a desired position of angle of rotation relative to the runner. The lower portion of the runner is cross-sectionally U-shaped and has two separate protrusions 18 on either side of the rule. These protrusions 18 steer the runner so that it cannot tip. In other terms, it is guaranteed that the runner be always kept in a vertical plane (whenever the stand is placed on a horizontal support) . The upper portion of the C-shaped arch part 4 has a relatively strongly dimensioned block or housing 19 with a vertical course, in which is mounted a rack 20 that carries the pressing means 5 at its lower end. In the housing 19 is built- in a gear (not shown) that, possibly via a suitable gear exchange arrangement, is rotatable manually by means of one or several arms 21. In the shown example, the carrier 2 placed in the region of the front side of the stand comprises two side pieces 22, 22', which in the region of the front ends are interconnec- ted via at least a rod 23 of polygonal, e.g. square, cross-section. The two side pieces, which have the form of elongated, comparatively wide plate elements, are articulatedly connected with two fixed ally arms 24, 24'. These are adjustable into different positions along the rule or box profile 8 in order to make the side pieces capable of receiving cylinder heads of differing lengths. The joint in question between a side piece and an ally arm is designated 25. According to the shown example, there is a clamping device 26 in connection with each such joint, by means of which clamping device the carrier may be adjusted to a desired angular position between a horizontal initial position and a position inclined forwards/downwards, as shown in Fig 1. Two blocks 27, 27' are mounted on the rod 23 and each block has a plurality of holes facing upwardly, in which a stop pin can be applied into a selectable position in order to hold a cylinder head on the inclined carrier in a desired depth position relative to the stand. Reference is now made to Fig 2 to 5, which inter alia illustrate the construction of a disk valve. The individual valve comprises a disk 29, a rod 30 and a compression spring 31 in the shape of at least one helical spring. The disk 29 cooperates with a valve seat in the bottom of a cavity 32 that opens into the bottom side of the cylinder head 3. Analogously, the spring 31 is accomodated in an upper cavity 33 that opens into the top side of the cylinder head. This upper cavity is very deep, wherefore the spring in its entirety is located far below the top side of the cylinder head. As may in particular be seen in Fig 4 and 5, the spring is locked relative to the valve rod 30 by means of a locking means that comprises on one hand a ring 34 with a conical seat, and on the other hand two equally conically shaped ring halves 35, 35', which on their inner sides have beads provided to engage into a groove 36 in the upper portion of the valve rod. The shown, preferred pressing means 5 comprises a vertical rod 38 that has an elongated, thin shape and that at its lower end has a ring-shaped ferrule 39, whose inside diameter is at least as large as the inside diameter of the locking ring 34. When the pressing means is pressed against the locking ring 34, the spring will be compressed to such a far-reaching extent that the two ring halves 35, 35' may be dismounted from the groove 36 and be withdrawn from the ring 34, as shown in Fig 4. Then the spring may be removed from the cavity 33, in addition to which the disk and the rod may be removed from the lower cavity 32. In Fig 6 it is illustrated how the post with the arch part and its rack 20 may be tilted relative to the vertical plane (either to the left or to the right relative to it) . The tilting is effected by detaching the clamping mechanism 17, in addition to which the shaft 15 is turned to the desired position of angle of rotation in relation to the runner 10, whereafter the clamping mechanism again is brought to lock the shaft. By the fact that the spring leaves 12, 12' have a large width, the arch part follows the post in one and the same upright plane, at the same time as the arch part still may be raised and lowered relative to the post thanks to the fact that the spring leaves are elastically flexible in a direction upwards and downwards . Further, in Fig 7 it is illustrated how the arch part 4 may be adjusted into different positions depthways relative to the stand. This adjustment is made by dislocating the shaft 15, after having detached the clamping mechanism 17, into the one or the other direction relative to the runner 10. In practice, cylinder heads for internal combustion engines often comprise two rows of valves in the region of the opposed long sides of the head, although merely one valve row is indicated in Fig 2 and 3. Operation and Advantages of the Invention When a disassembly of valves from a cylinder head is to be made, the cylinder head is placed on the carrier 2, besides which - after an adjustment of the distance between the side pieces 22, 22' - the carrier is adjusted into the correct oblique position at the same time as at least a rough positioning of the head takes place depthways, so that the valve row in question is located in the proximity of the pressing means 5. In addition to this, the pressing means per se may be fine- adjusted depthways by dislocating the arch part 4 and the post 11 to a desired position relative to the runner 10. In the case where the individual valves are tilted not only in relation to a central, longitudinally extending vertical plane through the head, but also in relation to a cross-plane that is perpendicu- lar to the former, also the arch part 4 and the pressing means 5 are adjusted into a desired position of obliquity. This is made in a previously described way, by detaching the locking mechanism 17 in order to permit a turning of the shaft 15 to a desired position of angle of rotation relative to the runner 10. When the individual valve is to be disassembled, the pressing means 5 is led in over the upper cavity 33 in the cylinder head. When this has been made, the ring ferrule 39 of the pressing means is lowered into said cavity, in that the operator, by means of the arms 21, applies manually a down- wardly directed force on the rack 20. As soon as the ring ferrule has come into contact with the locking means, the abutment 6 is brought to move upwardly into contact with the disk 29 by continued down- feed of the rack (the entire arch part moving upwards) . When this has been accomplished, the compression of the spring 31 is initiated and when the compression has been driven sufficiently far, the locking means may be removed from the valve rod in a previously described manner. Thereafter, the valve rod and the disk may be removed from the lower cavity 32. In a following step, when the pressing means is to be moved to the next valve in the same row, the rack 20 is brought to move upwards by means of the arms 21. By its own weight, the arch part 4 will then sink relative to the cylinder head, more precisely to a lower position in which the abutment 6 goes clear from the lower cavity 32 in the head. This lower end position is determined by the upper stop surface 41 of the groove 40. A continued raising of the rack 20 brings about that also the pressing means 5 is removed from the upper cavity 33. The lowering of the arch part 4 may be accomplished due to the flexibility vertically of the spring leaves 12, 12', without any skewing of the arch part laterally relative to the post 11 and without the parallelism of the middle portion 13 with the post 11 being lost. When a movement to the next valve has been accomplished, then the abutment tap 6 may again be led up into the lower cavity of the valve in question, by no other measure than the rack and the pressing means being moved down into the upper cavity, whereafter the described operation is repeated. Of course, compression springs may be compressed cor- respondingly, in connection with the assembly of valves in cylinder heads. An essential advantage of the spring compressing device according to the invention is that the required pressing means may be moved between different valves in a quick, smooth and simple way, without the total cost for the device becoming prohibitively large because of this. In turn, this implies that also small and medium size workshops may afford to purchase and handle the device in question. The invention is not restricted solely to the embodi- ment as described and shown in the drawings. Thus, the carrier for the cylinder head may be modified in many ways, e.g., by providing clamping or locking means for the side pieces on the ally arms, in connection with the rear or inner ends of the side pieces. It is also feasible to arrange the rod 23 in slots that are open upwardly, in the side pieces, in order to simplify the dismounting of the rod, when necessary. Instead of one sole wide spring leaf at the top and bottom ends of the post, two parallel spring leaves of reduced width may be used. Thus, instead of one sole spring leaf with a width of 40 mm, two mutually separate, parallel spring leaves with the width of 20 mm may be used.

Claims: CLAIMS 1. A device for compressing the compression springs of disk valves in motor cylinder heads comprising a C-shaped arch part (4) with an abutment (6) at a first free end and a pressing means (5) located at a second end, which pressing means is reciprocally movable by means of a force producer (20, 21) , c h a r a c t e r i z e d in that it comprises a stand (1) with on one hand a carrier (2) for placing a cylinder head (3) , and on the other hand a guide (7) , along which a holder (9) is reciprocally movable, with which holder the arch part (4) is connected via at least two vertically separated thin and wide spring leaves (12, 12') of an elongated shape, which on one hand are flexible upwards and downwards due to their small thickness, in order to enable a movement of the arch part bet- ween different vertical positions, and on the other hand are rigid laterally due to their width, in order to prevent the arch part from skewing laterally relative to the holder. 2. Device according to claim 1, c h a r a c t e - r i z e d in that the holder (9) comprises a runner (10) that is movable along the guide and has a through-hole for a shaft (15) that is rotatable relative to the runner, which shaft by a first end bears against a straight middle portion (13) of the arch part (4) , and at an opposed second end is co-rotatively connected with a shape-stiff post (11) , with which the spring leaves (12, 12') are connected. 3. Device according to claim 2, c h a r a c t e r i z e d in that the runner (10) comprises means (17) for fixing the shaft (15) in desired positions of angle of rotation, as well as axial positions, relative to the same. 4. Device according to claim 2 or 3, c h a r a c t e r i z e d in that the guide is composed of a rod-shaped or tubular element (7) below which is located a rule (8) for steering a lower portion of the runner, more specifically in an ever vertical state, and that the hole for said shaft (15) is provided in an upper portion of the runner and extends perpendicularly to the rod element . 5. Device according to any of the preceding claims, c h a r a c t e r i z e d in that the carrier (2) for the cylinder head (3) comprises two side pieces (22, 22') which are interconnected via a rod (23) or similar at ends distal from the arch part (4) , along which rod there are two axially separate stopping means (27, 27') with means (28) for stopping a cylinder head placed on the end pieces in one of several distal positions, and that the side pieces are pivotably mounted in bearings relative to the stand and lockable in different leaning positions frontwards/downwards from an initial horizontal position. 6. Device according to any of the preceding claims, c h a r a c t e r i z e d in that the force producer is provided at an upper end of the C-shaped arch part (4) and comprises a rack (20) carrying the pressing means (5) , which rack is ver- tically movable by a manually rotatable gear wheel. 7. Device according to any of the preceding claims, c h a r a c t e r i z e d in that the pressing means (5) is composed of on one hand a ring-shaped ferrule (39), and on the other hand of a rod (38) with a thin elongated shape, protruding from the former.

Inventors: LOWEMARK BENGT, LOWEMARK, BENGT
Applicants: LOWEMARK BENGT, TREGO MASKIN AB, LOWEMARK, BENGT
Application year: 1998
Main classification: B25B27
IPC codes: B25B11, B25B27