Technical field

This invention relates to the suspension device for the transport and surface treatment of combustion engine valves, which are designed to be carbonitrided, including all technology-related operations - degreasing, rinsing, carbonitriding, oxidation, blasting and transportation.

Current technology state

The valves in internal combustion engines represent parts with high demands in terms of the parameters of resistance to heat stress, wear and corrosion. The best finish of the surface has proved to be the so called carbonitrooxidation, a collective name including the oxidation and carbonitriding technology. Carbonitriding means surface layer enrichment of ferrous materials with nitrogen and small amounts of carbon. This chemical-heat treatment is used to improve wear resistance and fatigue strength. By using a subsequent cooling oxidizing bath, a dark appearance and improved corrosion resistance is achieved. After the carbonitriding process it's also possible and even preferred to cool directly in a water bath.

The carbonitriding process is performed so that the iron components are immersed in molten chemical salt at a certain temperature, which thereby causes hard-surfacing of these components. Depth of the hardened layer is therefore dependent on the original material, duration of the process and temperature. In order to maintain the quality of the obtained surface layer on the exposed parts of the components, they must be inserted into a molten liquid in special jigs - so called suspension devices. Currently used jigs for internal combustion engine valves, are designed so that individual pieces are vertically suspended on wire screens of different mesh sizes, depending on the valve type and size. The jigs serve therefore as separate suspenders, based on the diameter size of valve heads. The disadvantage of this solution is found mainly in the fact that the valves are hung vertically. Therefore the molten liquid adheres to the plate (the valve head) and creates a certain layer that is not able to flow down; which is particularly undesirable due to the high consumption of molten liquids. Another disadvantage is the fact that the jigs, in the form of wire screens, can always be used only for certain groups of valves, which are determined by the valve head diameter, and require more time to insert the control valves manually into the screen meshes. The Invention principle

The suspension device for the transport and surface treatment of combustion engine valves eliminates the above disadvantages through this invention, based on the jig suspension made of two circular steel rods, which are interlocked by means of at least two couplings. The gap width between the rods should be bigger than 1.1 times the diameter and smaller than 2 times the diameter of the valve stems which are inserted into the gap. The valves are fixed in the gap by the tilting of the suspension device. The invention principle abides also in the fact that the first couplings are placed on both sides of the jig at a distance from the rod ends which is larger than the width of the frame bar, over which the individual jigs are slipped. The valves are secured in the individual jigs by the tilting of the jig as a result of its own weight and the thereby created lever system - the jig with valves. The principle abides also in the fact, that the couplings are placed between the circular rods. Hanging the valves on the suspension device and putting them on the bar of the standard frame, leads to their tilting (hanging at an angle) and thus to easy flowing down of the molten liquid back into the salt bath, rather than being irreversibly delivered into the technology cooling system and further to the subsequent rinsing processes.

Thanks to the invention of this new suspension device, the input costs for chemistry, i.e. chemical salts, are significantly reduced due to the handing at an angle of the valves in the jig. An individual jig is not single-purpose for one valve size, it complies with valves of different stem diameters. Furthermore, inserting valves into the jig is much easier. Savings of production costs of the surface treatment of the valves, high productivity, and increased capacity of technological devices, are also connected with considerably lower hazardous waste disposal costs and thereby the impact on the environment is significantly reduced. Using the jig is beneficial even in other areas of thermal surface treatments and other ways of handling valves.

Pictures in the drawing

The invention of this new suspension device is closely explained in the accompanying drawings, where Figure 1 represents the view of the suspension device from above; Figure 3 relates to valve positioning within the tilted jig. Figures 4 and 5 represent the suspension device with valves from two perspectives, as it is placed in the drawer rack frame. Examples of the construction

Suspension device 1. consists of two circular steel rods 1Λ which are linked together by two couplings 1^2, so that the valves 4 could be inserted into the resulting gaps. The gap between the rods tj. is bigger than 1 ,1 times the diameter and smaller than 2 times the diameter of valve stems 4. The valves 4 are suspended via the nonfunctional part of the valve 4_i i.e. via the neck below the valve plate. Individual suspension devices 1 , on which the valves 4 are hung, are freely slid on the rails 2 of the frame 3 of the standard drawer stand, which is used for the carbonitrooxidation technology of steel parts. The first couplings JL2 on both sides of the suspension device i are placed at a distance from the rod U. endS which is larger than the width of the bar 2 of the frame 3. At the same time, the coupling \2. serves as a stopper which doesn't allow the individual suspension devices 1. to unfasten from the frame 3. Suspension devices 1 are slipped over the bars in a vertical position. Their number depends on the capacity (size) of the frame and the devices 1 are tilted - locked on the bars 2. The valves 4 are then fixed within each suspension device 1 by diagonal suspension, which will occur after the tilting of the respective suspension device 1. in the frame 3 due to the weight of the valves 4.

The tilting of the individual suspension devices can be obtained also by other systems of construction, where the products will be stored - which could be for example a device for tilting of individual suspension jigs.