How to place the Grover washer correctly

The spring washer, or as it is also called, the Grover, has found its wide application in all areas, especially mechanical engineering. Let us consider in more detail the features of its design, quality requirements, production, as well as situations in which it is impossible to do without it and, conversely, when the use of such a fastening element is unacceptable.

Spring washer - let’s get acquainted with the purpose of the product

Let's start with history, especially since its roots do not go back too far. It all started at the end of the 19th century, when the rapid development of mechanical engineering required new, better threaded connections. After all, standard types of nuts and bolts simply could not withstand all the loads, vibrations and vibrations falling on the moving parts of components and mechanisms.

Moreover, the consequences were of a very different nature; as a result of weakening or even unscrewing of fastening elements, the strength of the connections was significantly reduced, and fatigue failures occurred.

However, replacing this type of fastening with riveted ones was also not a solution. Firstly, they are not always convenient to use, which significantly hampered progress and the development of new elements.

Secondly, even if this worked somewhere, difficulties subsequently arose with the maintenance of such mechanisms. In general, a fundamentally new threaded connection was required that could withstand shock loads and act as a stopper, so to speak, which is what the lock washer became.

As you know, all the most ingenious things are incredibly simple things, this rule also applies to such a product. This washer looks like one coil of a spring, which is where the name comes from.

At the same time, it works flawlessly, due to the fact that its gap diverges in the direction opposite to the rotation of the nut, which prevents it from unscrewing. Thus, during forward stroke, the fastening unit moves without obstacles.

However, rotation in the opposite direction is prevented by the edge of the groover, which, as it were, digs into the metal and ensures the locking of the nut .

Grover washer - production and materials

The spring washer-grower (GOST 6402-70) must meet the requirements described in the above documentation. So, these elements are mainly made of steel, but bronze and other non-ferrous metals are also allowed, but we’ll talk about them in more detail below.

The hardness of steel products ranges from 40 to 48 HRC (Rockwell C units). If the material is St 70, then this parameter can reach 50 HRC, and bronze growers must have a hardness of at least 90 HRC.

The presence of burrs, scale, cracks, and pockets of corrosion is considered unacceptable defects. Traces of inseparable scale and minor defects in the cut plane, which do not affect either the dimensions or strength characteristics of the product, are acceptable.

The trapezoidal cross-section is also not considered defective, but only if it does not go beyond the permissible height. Such washers are also tested. After compression three times so that the diverging ends come together and a flat surface is formed, and further exposure for 24 hours in this state, the height of the divorced ends should be at least 1.65 parts of the thickness of the part. Of course, products should not break or crack.

Having familiarized ourselves with the requirements for this type of fasteners, we will consider some of the features of their production. Of course, all the parameters that the washer-grower must meet - dimensions, strength, permissible and unacceptable defects, material, as well as type of coating - are indicated in the technical documentation, such as GOST or DIN.

It is also worth noting that there are four types of such washers: normal (N), heavy (T), extra heavy (OT) and light (L). The first three types have a cross-section in the shape of a square, while the last ones have a rectangular cross-section.

Spring steel is very often used as a material, and then the part is subjected to heat treatment, due to which internal stresses in the alloy are relieved, its strength characteristics are increased, as well as resistance to external influences. In addition, fragility is reduced, and this is all incredibly important, especially considering the purpose of these parts.

But achieving the required properties is ensured not only by a set of heat treatment measures. This type of washers can also be coated with a special protective coating (chrome plating or galvanizing). True, this is not necessary, so growers are also available without coating.

Galvanizing and chrome plating primarily provide reliable protection against corrosion.

Galvanic galvanizing is carried out by electrochemical deposition of zinc particles onto the surface of a part, which is previously placed in an electrolyte. As a result, a layer with a thickness not exceeding 25 microns is formed, and the washer acquires a blue, white or rainbow tint.

How to install the Grover washer?

As for its location, there is no fundamental difference whether it will be installed under the bolt head or under the nut. You can even use two elements at the same time, and then the effect will be doubled.

The peculiarity of this fastener is that the larger the cross-section of the ring in width and height, the higher the indicators of the developed elastic force, however, such changes do not in any way affect the value of elastic deformation. In addition, the tightening force is distributed unevenly over the entire circumference; its peaks occur in the area where the ratchet teeth are located.

How to install correctly?

There is a set of rules for installing bolted connections using Grover washers. They all boil down to the following.

You cannot use steel lock washers with bronze or aluminum nuts. Burrs and differences in the cross-sectional plane of the grower leave grooves on them when tightening non-ferrous metal nuts, which can lead to breakage of the nut.
The bushing connection must not be overtightened. Tightening a nut of any size in any case flattens the part, turning it into a regular gasket with almost no spring effect.
You cannot place a bushing washer under the pressing washer. The second one should be further away from the nut and/or bolt head than the first one. That is, the bolted connection is completed in the following sequence: bolt head, lock washer, press washer, workpieces to be fastened, press washer, lock washer, nut - nothing else. More specifically, the washers are installed in a mirror sequence on both sides of the parts being fastened.
It is unacceptable to clamp the grower washer between two pressing tools. If the bolt is long and the thread is not cut along its entire length, but there is an unoccupied gap between the nut and the fastened parts, then first one or more press washers are installed, then one or more lock washers, and finally the nut is screwed in. That is, the press and grower washers should not alternate either randomly or cyclically. The configuration is reminiscent of the correct loading of a training barbell. The method of “mirroring” washers is also valid in this case.

The use of bronze lock washers with steel nuts and bolts will not give the effect: neither aluminum alloy nor bronze will give the expected effect. Use only high-quality steel fasteners, not counterfeits.

Source

Application of spring washers and operating features

Such fasteners have found wide application in the automotive industry, construction, engineering and industrial sectors, as well as in many other areas. In general, it is difficult to imagine an area in which this special-purpose washer would not be used.

Such products are an indispensable part of many components and mechanisms, especially if the latter experience shock and vibration loads that contribute to the loosening of bolted joints. But quite often these fastening points are entrusted with a very responsible mission, so even their weakening, let alone completely unscrewing, can lead to very dangerous consequences.

So, the use of spring washers is very common, but we will also consider cases when you should not give preference to this type of fastener. As already mentioned, the locking effect of the nut is achieved due to the sharp edges of the groover, which, after tightening the ring, seem to cut into the supporting surfaces.

Thus, if the latter are not hard enough, then the indentation is too pronounced. Therefore, the use of a grower in combination with soft metals and alloys, for example, magnesium, aluminum and others, is unacceptable, since as a result the surface of the product will be damaged.

"Grover" is a designation applied to spring washers. This is a backing piece designed to be used in conjunction with nuts and sometimes other types of fasteners if a nut cannot be installed. The peculiarity of washers of this type is the presence of a specific cut, due to which their ends are located in different planes. Due to this design, the Grover washer effectively prevents spontaneous loosening of the fasteners.

What do you put under the nut?

Roofing types of washers have sealing gaskets made of rubber or rubber. ... Washers with claws are a kind of stopper. They are used to fix the fastening device in order to prevent the nut from turning with the backing when exposed to dynamic and vibration loads.

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Scope of application and characteristics of growers

Structurally, the “grower” is an elastic split ring. When the washer is pressed with a nut, tension is created, and the sharp edges of the “grower” cut into the body of the fastener and the surface of the fastened part, thereby preventing spontaneous unwinding of the connection. Due to elastic decompression, the washer is able to lock itself and ensure maximum reliability of fastening. Thanks to this, this type of fastener is widely used, allowing you to create strong, reliable connections without damaging the parts and materials being connected.

This type of washers performs several important functions:

seals the connection;
evenly distributes the load from the fastener over the pressing surface;
allows you to avoid distortions when tightening fasteners;
prevents fasteners from falling into the installation hole.

In accordance with GOST 6402-70, bushing washers are divided into 4 classes according to the level of resistance to elastic deformation and cross-sectional dimensions:

How to install a grower correctly?

This type of washer is intended for installation under the head of a nut, but if a bolt or threaded rod is embedded in the body of some parts, it is permissible to install a “grower” under the head of the bolt. In this case, it is important to press the washer as tightly as possible with the head of the fastener, otherwise its use will not make sense.

The PARTNER group of companies supplies throughout Russia high-quality fasteners and hardware, both its own production and from leading foreign and domestic manufacturers. In our catalog you will find growers made of galvanized spring and stainless steel.

We offer washers of the most popular sizes: M4, M5, M6, M8, M10, M12, M16, M20, M24, etc. Detailed size tables, weight of 1 piece and other parameters of growers can be found on the product page in the PARTNER Group catalog. Here you will find washers manufactured according to German standards DIN 7980, DIN 127, as well as according to national GOST 6402-70.

You can buy growers wholesale from the manufacturer PARTNER Group by placing an order on the website or by phone. Representative offices of our company are located in Moscow and St. Petersburg, as well as 47 other cities in Russia, which allows us to deliver orders as quickly as possible.

What is it and what is it for?

A spring washer is needed to forcefully fix a nut screwed onto a bolt, and it is used only once - for each specific connection. This means that its use is justified only in the case of a one-time bolted installation. After dismantling, since it loses a significant part of the springing effect, re-screwing it even onto the same nut-bolt joint is not recommended. Since bodies with ideal elasticity do not exist in nature, any body with prolonged or excessive compression partially loses its property. It is similar to the way a ball bounces up to a different level from where it fell: the oscillations of the body on a spring - Grover's washer is just a coil of such a spring - will eventually disappear. Repeatedly tightening the locking washer turns it into a regular press washer, equal in area to the place where the nut comes into contact with the edge of the part being fastened, which it holds in place.

The spring washer, as a subtype of the locking gasket, was primarily used in mechanical engineering, and then spread to the production of electrics, electronics, and all kinds of automation. It is used to secure critical parts of machines, mechanisms and electrical components. For example, this washer is used to prevent the load-bearing structures of a carriage, car body, or desktop computer system unit from coming loose. The electrical contacts of switches, circuit breakers, circuit breakers, telephone terminal blocks in the automatic telephone exchange are fixed to it. Wherever blocks with wires fit, where reliable contact of a power or signal line is needed, at least one bushing washer is used - for one such wire with a C-shaped contact, vaguely reminiscent of a simple block.

An example of use is electric motor terminals: significant starting currents force us to provide a very reliable contact in which there will be no sparking.

Grover washer - the history of the creation of a new type of locking connection according to Gosstandart

At the end of the 19th century, the mechanical engineering field began to develop at a fairly high speed, which required new, more reliable connection methods. The quality of threaded connections at that time was low, and conventional versions could not withstand oscillatory loads and strong vibration. Due to this effect, the strength of the connection is significantly reduced, and other common problems associated with loss of tightness could arise. The situation was significantly improved by a spring washer, which significantly increased the strength and reliability of connections in the event of a vibration load.

The new type of connecting element is quite simple, which determines low cost and reliability in use. GOST 6402-70 spring washers determines the use of certain materials in their production. The key points are:

Reminds me of a regular spring coil.
The gap diverges in the direction opposite to the movement of the nut, thereby eliminating the possibility of unscrewing.
The rotation is fixed due to a special edge of the grower, which digs into the surface.

When designating and marking a spring washer, it is indicated what material is used and the diametrical size. It is worth considering that not all materials are suitable for the manufacture of the product in question, since it is necessary to ensure high performance characteristics.

Washer compliance with GOST 6402

The grower is manufactured as specified in GOST (spring steel 65G), followed by heat treatment. This reduces the internal stress of the metal, increases its strength and resistance to external influences, and also reduces the fragility of the product.

Grover washers can be produced with or without coating. The applied coating improves the anti-corrosion properties, and the chrome coating also gives greater hardness to the washer and increases service life.

Grover disc is available in four types: light, normal, heavy and extra heavy. GOST describes all the indicators that spring washers must have, and also presents a table of dimensions of the washer-grower. The type of disk is influenced by the profile of the wire rod.

The sharp edge of the disk also stops spontaneous unscrewing due to the emphasis on the metal, therefore, when it is necessary to unscrew the fastener, mechanical damage (scratches) usually remains on the nut from the sharp edge as if from a carver.

It is not recommended to use the disk in an assembly with fasteners a second time, and when this recommendation is ignored, the fasteners are unscrewed at the most inopportune moment.

Grover washer options

Most often, the product in question is used to ensure a reliable bolted connection. At the same time, it is often installed with a conventional design to significantly increase the contact area. Due to this, the reliability of the connection is significantly increased. Looking at the product drawing, two different versions can be noted:

The first one is considered the simplest. Considering the din 127 spring washer, we note that it has a different hole diameter, as well as coil thickness. In this case, a certain angle of deviation of the turns from the central axis is noted.
The second version is characterized by greater complexity in production. However, due to the complexity, the mechanism can withstand large dynamic and multidirectional loads.

The din127 m8 galvanized washer has become quite widespread. Due to special treatment, the protection of the surface from environmental influences is significantly increased. Also sold is a din 7980 m6 washer, which is characterized by its own specific features.

Most products have right-hand winding, due to which the production of hardware is carried out in a clockwise direction. But some versions are made with a left-hand turn.

Contact grooved washer

In a specialized store you can also find a product with a corrugated surface. Their scope of application is to ensure connection reliability. Corrugation of the contact surface can significantly increase the degree of adhesion between two products. The key points are the following:

In most cases, spring steel is used in the manufacture of the main part, which is characterized by increased elasticity and wear resistance.
The diameter of the washer is selected depending on the size of the part.
Often, to significantly increase the degree of protection of a surface from environmental influences, the surface is coated with zinc or plastic.

It is worth considering that a complex contact surface causes a significant increase in the cost of the washer.

That is why it is used only when creating critical products that can withstand severe variable or constant loads.

Disadvantages of the Grover Washer

Before paying attention to the disadvantages, we first note the main advantage - the simplicity of production technology and low cost. However, there are also several serious disadvantages that need to be taken into account:

In some cases, the force of the spring washer is not enough due to the high dynamic loads that arise during operation of the mechanism.
A large tension force causes the grower to turn into a regular plate. Fixation is provided only to a small extent.
In almost all cases, the connecting element in question cannot be reused due to severe deformation.

When creating conventional devices, a spring washer is used due to its low cost. In some cases, the possibility of replacing it with another product with a similar scope is considered.

Comparison of different types of washers

Above, information was presented about the main types, advantages and disadvantages of available methods of locking threaded fasteners. However, which one is better? In particular, which washers are more appropriate to use in specific conditions?

The answer to this question can only be given by comparative tests. To assess the endurance of bolted connections under dynamic load conditions, special vibration stands are used. The measuring complex includes a platform on hydraulic supports, an external electric motor (for loading the platform - creating vibration) and control sensors, information from which is sent to a PC for subsequent processing and demonstration of the results.

The tests are carried out as follows. Fasteners (bolt, nuts and washer) are installed into the hole on the platform and tightened with a primary torque (for example, 8 kN). The engine turns on and the platform begins to vibrate. After some time, the connection will “float”, i.e. the nut will begin to unscrew spontaneously and the primary tightening torque will decrease - perhaps even to zero (the fastener will completely loosen).

Which washer locks the connection better? Obviously the one with which the primary tightening torque under the influence of vibration will last longer! The relationship “moment – loading time” allows us to draw a conclusion about the durability of the washers. And at the same time, compare them with each other - under the same experimental conditions.

Such a test is called the “Junker vibration test” (the test procedure is regulated by DIN 651512002). The test shows that the lock (wedge) washer has the greatest resistance - the primary tightening torque is maintained almost 100% (while, for example, with a lock washer it drops to zero by the end of the test!).

How can I replace a spring washer on a Grover?

You can fix the nut using a variety of elements; quite a lot of them have been produced. Grover, another name for a spring washer, is often replaced with the following:

The nut is self-locking. This product is characterized by the fact that in the upper part there is a plastic rate, which is responsible for damping the vibration load and unwinding. It is worth considering that difficulties in manufacturing the product cause a significant increase in its cost, but the effectiveness of such a nut is quite high.
Disc type washer. It can also be installed instead of the original grower, and is characterized by lower cost and greater reliability.
There is also a crown nut. It is required when drilling a counter fastening element and then placing a cotter pin. The reliability of the connection in this case is quite high, but it is characterized by steps.
Gear type flange. The flange has notches that are fused with the nut. The notches ensure reliable fixation of the connection.
Lock washer. During its manufacture, a large number of teeth are created that provide fixation.
Plates with antennae. In this case, one of the tendrils is selected into the part, and the rest are folded over the turns. There are simply a huge number of similar versions on sale, so it is possible to choose the most suitable one.
Wire locks. This fixation option has become widespread due to its low cost.

As a rule, the choice is made depending on the operating conditions.

NORD-LOCK washers

NORD-LOCK washers are progressive fasteners in threaded connections. Its use prevents the connection from self-unwinding. The special design of such fasteners not only prevents spontaneous unscrewing, but also maintains pre-tension in the connection.

The NORD-LOCK fastener uses a wedge-locking effect to maintain the strength of the connection. The basis for fixing a connection with the help of such hardware is primarily pre-tension (in conventional friction). Structurally, the NORD-LOCK washer consists of 2 washers, the lower and upper sides of which are shaped like teeth (wedges) that prevent spontaneous unscrewing. Thanks to the cone-shaped shape, the pre-tension is maintained in the connection for a long time, even if the bolt and nut are made of a “relaxing”, soft material.

The Krepcom online store offers you to buy washers, bolts, nuts, studs and other fasteners at attractive prices. We have a large selection of payment methods, sending goods by transport companies to any city. Articles about products 09.20.2019 14:21:09

Varieties, material and manufacturing methods

The product in question is manufactured taking into account the standards established in GOST 6402-70. It specifies what materials and methods should be used. Among the features of the choice of metal, we note the following points:

It is allowed to use steel, as well as bronze and some other non-ferrous alloys.
Hardness should vary from 40 to 48 HRC when using common steel grades. If bronze is used, the value is at least 90 HRC. The weight and some other indicators largely depend on the type of material used.
During production, various methods can be used, but the appearance of cracks, scale, burrs and other defects is not allowed. In some cases, only minor defects are acceptable that do not affect the performance characteristics of the product.
To identify the main qualities, a flat washer is subjected to various tests.

A situation often occurs when, in the manufacture of a spring washer, special spring steel is used, which has special performance characteristics.

To achieve the required properties, heat treatment is carried out, due to which the hardness increases and the brittleness decreases.

Material

According to GOST 6402 (as amended in 1970), the material for bushing parts is steel 65-G. It is a type of high-carbon steel useful in the manufacture of spring springs for land vehicles and a variety of special equipment used in large-scale construction. An exception to this rule is the use of bronze alloys.

However, bronze, unlike “spring” steel, almost does not have the same elasticity, and it is used extremely rarely in serious structures.

How to install the Grover washer?

In general, the product in question does not differ significantly from the usual version. That is why the installation features include the following:

Located between the nut and the main element.
Can be supplied with a regular nut.

It is the ease of operation that determines the wide distribution of the product in question.

Installing the Grover Washer

The process of installing hardware differs slightly from the standard installation of other similar fasteners. Among the main features are the following:

the structure is placed between the nut and the part being connected;
Grover can be used in conjunction with conventional nuts.

The spring nut is in demand due to its ease of use. Therefore, it is found in various fields as temporary or permanent fasteners. It is better to replace the part with a more expensive one over time for several reasons:

the grower is susceptible to mechanical damage;
cannot be reused due to deformation;
technical properties decrease over time.

It is not recommended to use a locking washer for critical connections.

Application of spring washers and operating features

The scope of application of hardware and the spring washers in question is quite wide. This is due to the fact that they are easy to manufacture and last for a long period. Among the operating features we note:

Over time, the basic properties decrease.
Mechanical damage can cause failure.
Exposure to heat also negatively affects the basic properties.

It is allowed to use a washer of this type in mechanical engineering and other fields. This takes into account that the degree of fixation is relatively low.

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Grover

(also
Grover washer
, named after the inventor [1], D. Grover (English) Russian, who founded the English Grover & Co., Ltd [2]) - a spring split washer designed for use as a locking element to prevent unwinding threaded connection.

The Grover is made of spring (hardened or stainless) steel in the form of a cut ring (left spiral). Bronze, aluminum, and Monel metal are also used as materials [3].

Design and technical requirements

The spring washer is manufactured in accordance with the requirements of GOST 6402-70.

Structurally, the part looks like a ring of square wire (s), cut in one place at an angle of 70 degrees to the plane of the washer. The width of the cut is 0.75 s. The ends of the cut are spread in different directions to size h, depending on the type of execution.

There are 2 versions available, differing in size h. In the first version, the size h is equal to 2s, in the second - 2s+2k, where k is the height of the pointed edge. Version 2 is more difficult to manufacture, but can withstand higher loads.

Available in 4 types:

N - normal, with a square cross-section;
T - heavy with a square cross section;
OT - especially heavy, with a square cross-section;
L - light, with a rectangular cross-section.

In modifications N, T, OT, for each nominal diameter of the washer, the cross-section increases, and the spring stiffness of the washer increases accordingly.

Washers are made from square wire from steels 65G, 70 and 30X13. For “light” ones, the wire cross-section is rectangular.
After giving the grower the required shape and size, the part is subjected to heat treatment to ensure the required hardness HRCe 40 .. 49.
To increase corrosion resistance, parts are subjected to bluing (Chem. ox), galvanizing, nickel plating, and chrome plating.
All sizes of spring washers are indicated in the table.

The size table of the washer-grower from GOST 6402 can be viewed (https:///document/1200004378).

Action [edit | edit code]

When tightening the connection, the sharp edges of the groover, placed between the part being connected and the nut (or screw head), cut into the flat surfaces of the connection and subsequently prevent the connection from coming loose from vibrations. This mechanism of action makes growers ineffective on left-handed threads or very hard surfaces.

The effectiveness and reliability of growers were questioned at the end of the 20th century [4]. The Society of Automotive Engineers has not recommended them for critical connections since 1969 [ source unspecified 654 days

] .

Locking bolted connections

Countering: the simplest and most obvious way to securely tighten a nut is to screw another one on top! The second nut (lock nut) will reliably press the first one, forming an almost monolithic pair with it. The advantage of this method is ease of installation (using only standard products). The disadvantages are increased (maximum double) consumption of nuts, increased weight and dimensions of fasteners.

A spring (in common parlance, a “grever”) washer is a split elastic ring. When it is pressed with a nut, tension is created, and the sharp edges of the washer cut into the body of the nut and the surface of the part, preventing self-unwinding. Even if, under the influence of vibration, the nut moves out of its position, the elastic release of the locking washer again creates tension and the connection literally locks itself. The advantage of the method: simplicity and reliability. Disadvantages - the need for an additional assembly unit (grip washer), possible errors, forgetfulness during installation, damage to fasteners and the surface of the part by the sharp ends of the washer during tightening.

Self-locking nuts are a kind of synthesis of previous methods, when the nut and locking washer are combined into a single unit. Self-locking nuts have several implementation options. For example, a bolt and nut with a variable thread pitch - this achieves tension when screwing, preventing the connection from loosening during operation. Another option is the presence of an elastic (nylon or polymer) ring or petal notch in the upper flange of the nut. After tightening, these additional elements put pressure on the thread and, due to friction, “prevent” the nut from unscrewing. The third method is to connect a nut and a flat washer with a grooved “spring” surface into a single unit. When such a nut is tightened, the lower “washer” part is deformed, creating tension and preventing the fastener from unscrewing. The advantages of self-locking nuts of any type are ease of installation and the absence of additional locking elements. The disadvantage is that the design/shape of the nut is more complicated than the standard one.

Cottering - a short piece of doubled wire (cotter pin) is passed through a hole in the bolt shank and the body/crown of the nut, and then released. Advantages - perhaps the most reliable method of locking fasteners, the presence/absence of a cotter pin is easy to distinguish visually, and comparative ease of installation. Disadvantages - complicated design (hole in the body of the bolt, “spiky” crown on the nut), difficulty in unscrewing (cotter pins are most often disposable).

Punching, soldering, welding, riveting - allow you to create a conditionally detachable connection when the outer threads of the nut are damaged at a point. This creates a mechanical obstacle to movement along the thread. The advantage of the method is the reliability of locking. Disadvantages: damage to fasteners, difficulties both during installation (the need for welding, soldering or precision impact) and dismantling.

Applying varnishes, paints, and glue to threads - the method is similar to the previous one, but without mechanical damage to the threads. It’s a little easier to install (apply glue rather than soldering/welding!), but has a lower load-bearing capacity compared to punching and similar “mechanical” methods of damaging threads.

Lock (wedge) washers - consist of two “halves”, the inner surfaces of which are equipped with special wedge-shaped protrusions (hence the name). The outer edges of the washer also have projections (radial notches) for better adhesion to the surface of the part and the nut. When tightening the fastener, the halves of the lock washer are pressed tightly against each other without gaps - no deformation of the washer occurs. However, when the nut tries to move in the opposite direction (start to unscrew spontaneously), the inner wedges of the washer halves press on each other and “spread” outward - against the tightening force. Since the angle of the wedges is greater than the angle of the thread (this was taken into account when developing the washer), under the influence of vibration it is more likely that the nut will remain in place (not loosen!) than overcome the total “lift” of the thread and washer wedges. Even when operating the connection in conditions of strong vibration! Advantages: ease of installation, almost standard thickness of the lock washer (no additional elements), the ability to unscrew the connection without damaging the fasteners, repeated reuse of washers

Disadvantages: requires care during assembly (it is important not to confuse the installation of the halves - with the wedges facing each other, with the notch outward!).

Standards [edit | edit code ]

According to GOST 6402, washers can be manufactured in four types (light, normal, heavy, extra heavy). The difference between the types lies in the cross-sectional dimensions of the washer and the amount of force required for its elastic deformation. Washers can be made of spring steel grades 65G, 70, 30X13. It is possible to manufacture from bronze (grade BrKMts 3-1 GOST 18175-78) or other non-ferrous alloys. The hardness of steel washers should be 40-48 HRC, bronze washers - at least 90 HRB. According to GOST 27017, the term “Grover washer” is an unacceptable synonym for the term “spring washer” and should not be used in all types of documentation and literature that are within the scope of standardization or using the results of this activity.

Standards for growers:

GOST 6402-70
— Spring washers. Technical specifications;
DIN 127 B
- Stainless lock washer with smooth ends (spring washer with blunt edges);
DIN 127 A
- Stainless lock washer with tang end (spring washer with sharp edges);
NASM 35338
ASME B18.21.1

which is correct and which is best, or you can do both here and there at the same time

A Grover washer or a spring split washer is used to prevent spontaneous loosening of the bolt or nut. It was invented as a simple and cheap fastening element at the dawn of technological progress and has not yet left the arena, which means it’s not a bad thing.

Perhaps one of its few disadvantages is that it becomes a simple flat washer when tightened and begins to work only when “slightly loosened.” But this was avoided with two turns, which are still held in high esteem on railway rails. Moreover, the fact that it (the washer) is disposable, after the first use (unscrewing) it loses its functions.

They put a grower, from personal experience, under what they are spinning. Turn the nut - under the nut, turn the bolt - under the bolt. It makes no sense on either side.

Types of Grover Washers

Having described what an engraving washer is

, it is necessary to list the options for its implementation. The cross section can be square or rectangular. There are washers with outward curved edges. They are more difficult to manufacture, but this design can withstand higher loads and be used in heavy industry.

Engraving washer according to GOST

6402 can be one of four types - light, normal, heavy or extra heavy.
Their main differences are related to the different cross-sectional dimensions of the product. The larger this size, the higher the force required for elastic deformation of the bushing washer
. According to the same GOST, the hardness of steel washers should be in the range from 40 to 48 HRC, and of bronze products - 90 HRB or higher.

Alternative options for locking

In the process of tightening the screw pair, the twisted ring is compressed and takes the shape of an ordinary washer. The friction force is higher, but the tension effect will still not be very large.

Therefore, even if you use a part included in the catalog of the best growers, the risk of reducing the fastening strength still remains. An alternative can be found - there are several such options:

self-locking nut;
Belleville nut with spring effect;
nuts of crown type and with a cylindrical belt;
toothed flange;
locking washers and with antennae, etc.

The use of screw-type washers helps to ensure a more durable fastening and significantly reduces the risk of parts coming loose. For different base materials and screwing directions, you can select the appropriate type of ring or replace it with an alternative locking method.

Kinds

To finally understand whether a locking washer is suitable in your situation, it is useful for the technician to find out what can replace this product. Alternative options will allow you to fix the nut relative to the bolt no worse than a grower.

Self-locking nuts have a plastic insert used to reduce recoil from shock and vibration. But due to the relative complexity - compared to a washer-grower - a self-locking nut is noticeably more expensive, since in addition to steel of a certain shape, other, less hard and more elastic materials are used.

Disc-shaped - one of the standard options for replacing a grower. A more reliable and cheaper type of washers. Its closest analogue is conical.

Crown nut - used to create conditions suitable for installing a cotter pin through a separate hole. Thanks to the stepwise construction, it is recognized as one of the most reliable methods.

The serrated flange is suitable for groove joints. From the outside it seems that the steps on both sides fit into each other - due to their “helical” arrangement. The reliability of the connection and the prevention of loosening of the nut is not inferior to that of a grower.

The locking washer is distinguished by repeating spikes protruding at a slight angle relative to the plane of the main surface of the product. These teeth also press into the nut, preventing it from coming loose.

A washer with burrs allows one of them to be left within the workpiece, thanks to which the remaining ones bend around the turns. It comes in several varieties, specific to a particular situation.

Wire clamps are characterized by extremely low cost and the simplest production technology.

By bending an ordinary press washer, you get the simplest wavy washer - for example, for M6, M8, M10 nuts. But a truly springy wave washer is made from a thinner strip of steel than a regular wave washer, bent in a circle. The cut, like that of a grower washer, is absent in the wave one.

The purpose of the product is to eliminate the longitudinal movement of the rotor during engine operation.

For example, Belleville washers are used as a kind of shock absorbers that absorb shock and vibration on bolted fasteners. The main part of the impact falls on them - the nut and bolt will remain intact. Manufactured from spring-spring high-carbon steel. Corresponds to GOST No. 3057 (as amended in 1990). When using Belleville washers, the tension in a bolted joint is stabilized, sudden moments of force are eliminated, and in a narrow space they are used as a twisted spring (one turn). The purpose of the washer is to absorb heat-cold temperature fluctuations, which under normal conditions lead to damage to the nut and bolt used without any washers. Some manufacturers, trying to save more on production and packaging of a whole range of household goods, deliberately do not include bushing washers in the package. The consumer, seeing that they are not there, buys additional “grovers” on his own before finally assembling the thing or object that uses bolted connections.

Simple

A simple spring part is a coil of spring. Theoretically, it seems that to solve the problem with Grover washers, it is enough to take a grinder with a thin disk, or another saw, for example, a thin disk on a sawing machine and, having fixed, for example, a spring from a clamshell in a vice, saw it lengthwise - on the one hand, carefully while controlling the sawing to avoid cutting from the diametrically opposite side. Washers with a round cross-section made from such a “wire” (a spring is essentially a high-carbon steel wire that has good elasticity when compressed from the ends) can indeed solve the problem of tightening the connection.

By the way, simple washers are a smooth spring coil without burrs. The transverse cuts - the ends of the sawn spring coil-ring - are shifted, they do not “aim” exactly at each other. If they really coincided, such a part would be useless: it would not fix the nut at the moment of tightening, which means that such a steel gasket has no reason to be called a locker.

The cut of the ring is made at an angle of 70 degrees, and not conventionally perpendicular to the tangent passing through the point (line, internal edges) of the cut.

Complex

These components are called complex primarily because this element was developed for complicated operating conditions of structures and mechanisms, such as rotational movements of mechanisms. In particular, the aggressive manner of driving cars with frequent overloads, the operator’s manipulations of special equipment, accompanied by special working conditions, for example, a truck crane when lifting and carrying piles in weight at a significant height, and so on.

The second factor is the two-turn design. These are two successive turns with the same cross-section as simple washers. In other words, a “double” washer is a piece of a spring, the coils of which were deliberately “forgotten” to be divided, cut along the same line. The section of the coil at any point is not round, like that of ordinary springs, but rectangular; less common are trapezoidal profiled washers, in which the lower edge of the spring coil, which they are, is slightly longer than the top, while the side edges are directed upward, slightly beveled. The prototype of double-turn washers are sections of a spring with several turns. The scope of application is not only as a grower pad, but also as full-fledged springs in extremely narrow spaces. The elasticity, the resistance of two turns compared to one (single) also increases noticeably.

The spring part does not have the property inherent in its “non-spring” competitors: it cannot be combined as a single whole with a nut, bolt, or press washer. This is, as a rule, an independent and disposable element, easily changed during subsequent reinstallation of bolted connections.

What is the lock nut for?

Locknut - a locking element, a nut that is screwed in front of the main nut to prevent the threaded connection from unscrewing. Often it is made thinner than the main nut (2/3 of the thickness) and without changing other parameters of the nut.

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Mechanical engineering

Message from Nam3 : In what cases is a washer added under the bolt head to a bolted connection, and in what cases is it added under the nut? When should a washer be placed under both the nut and the head?

Copied from SP70

Without controlled tension: No more than two round washers should be installed under the nuts (GOST 11371). It is allowed to install one similar washer under the bolt heads. Solutions to prevent self-unscrewing of nuts - installation of spring washers (GOST 6402), locknuts or other methods of securing nuts against self-unscrewing - must be indicated in the working drawings of the KM brand.

With controlled: Regardless of the method of tensioning the bolts, the responsible person, within no more than two shifts, must carry out an external inspection of all supplied bolts and make sure that all connection bolts have the established markings and the same length; washers are placed under the heads of the bolts and nuts; parts of the bolts protruding beyond the nuts have at least one thread with a full profile above the nut or two threads below the nut (inside the package); the axial tension forces of the bolts correspond to those indicated in the drawing of the KM brand; the assembled unit bears the mark of the team that performed this work, and the results are recorded in the “Log of Tension-Controlled Bolted Connections” (Appendix E).

I never thought about it, and no one mentioned any rules. The only thing we have already noticed above is that they place it under what they rotate. Those. usually under the nut. This is due to the fact that when tightening, some compression of the surface of the parts being tightened occurs. And then it’s difficult to unscrew because of this. To eliminate this, they put a puck. Even if the washer itself crushes the surface, the nut on the washer will not experience resistance. Now, if for some reason it is more convenient to twist the bolt (the nut is difficult to access or even in a hexagonal socket), then you should put it under the head.

I haven’t seen it put on both sides. If memory serves. Although no one will prohibit it.

Message from Nam3 : And if we consider this design: there is a column (an axis with a thread at the end) on which a nut is screwed. A plate is placed on this nut, and another nut is screwed on top. Under which of the nuts should a washer be placed and is it necessary to stop this connection from unwinding?

Message from Nam3 : And if we consider this design:

For reasons of the seventh post, if you install it, it will be under the top nut. But for such a sandwich, in principle, you can do without washers. Well, if the plate is not completely soft. On the control - HZ. It seems to be close to the two-nut method, but there is a spacer between them. You have to look at the place. But without the ability to really determine, I would still be on the safe side.

As for spring washers - they don’t work well, they’ve already been discussed here several times. It is better to use nuts with a notched skirt.

Another nuance: according to GOST, it is prohibited to install washers between the flange and nut on pipeline flanges at pressures above 10 MPa.

Antonio_v

, what is there with the reference to the Eurocode?

A comprehensive answer can only be given by knowing the degree of responsibility of the connection. There are two fundamentally different approaches. Counter with friction force or under pressure. The split washer (growers and multi-claw varieties) seems to combine both. An example of friction locking is adding a lock nut. But there are known cases when both nuts, having merged together, move freely as a pair. In critical cases, the connection is secured with a stop. Examples. A washer with a mustache for round nuts, washers that can be bent to the edge of a fixed part, the use of a regular cotter pin. Conventional round smooth washers (normal, enlarged, reduced) are more designed to protect the surfaces of structural parts during frequent “reassemblies” from loss of presentation. Something like this.

Message from PavelVolk : Flange connection of trusses using high-strength bolts with controlled tightening torque. The question is: should I lock the nut or not, and what regulatory document can I look at?

Logically speaking, if the tightening torque is controlled, then it should be maintained during operation. That is, it must be secured in its original position with a locking device, even if the regulatory document does not say anything about this.

SP 70.13330.2012: 4.6 Mounting connections on bolts, including high-strength ones, with controlled tension 4.6.12 Nuts tightened to the design torque in accordance with 4.6.9 or rotated through a certain angle should not be further secured with anything.

Message from kubik1986 : SP 70.13330.2012: 4.6 Mounting connections on bolts, including high-strength ones, with controlled tension 4.6.12 Nuts tightened to the design torque in accordance with 4.6.9 or rotated at a certain angle should not be further secured with anything .

There are RDs either for flange connections or something similar. SP 16 Steel structures. The nut must be secured with a second nut or other means in SP 16. But all builders of their own free will use only 2 nuts. Because they are afraid. Yes, this is a controversial issue for a long time. In addition, high-strength connections have many operating and installation requirements.

Question to the author. How can you do CMD for a long time in Advance and not know this? Isn't it scary? And are you glad that you were allowed not to install the second nut?

Message from Tyhig : Question to the author. How can you do CMD for a long time in Advance and not know this? Isn't it scary? And are you glad that you were allowed not to install the second nut?