Box tenoning machines

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Woodworking machines

Box tenoning machines

Machine design. Tenoning machines for box tenons are of two types: for producing straight or wedge tenons (ShPK -40) and trapezoidal box tenons at the ends of workpieces. dovetail"(SHLH -3, SHLH -4).

The single-sided tenon-cutting machine for producing straight and wedge tenons ShPK-40 is designed for processing tenons at one end of the workpiece and can be used in carpentry, construction, furniture and other woodworking industries. The machine allows you to process workpieces up to 400 mm wide when forming straight box tenons and up to 110 mm when making wedge tenons. You can process several workpieces (package) with a total thickness of no more than 100 mm at the same time. The length of the workpieces must be at least 250 mm. The longest length of straight tenons produced is 50 mm, wedge ones - 10 mm.

A horizontal milling shaft, a lifting table and a hydraulic unit are mounted on a box-shaped frame.

The milling shaft is made in the form of a spindle with replaceable sets of cutters mounted on it. The spindle is mounted on two supports. The right support is provided by two angular contact bearings. The left removable bearing is a radial spherical ball bearing with a hub into which the end of the spindle fits. The removable support bracket can be tilted 90°, freeing up an area at the end for tool replacement.

The spindle is driven by an electric motor, which is mounted on a rotating plate so that the tension of the toothed transmission belt can be adjusted. Table 5 is moved along the frame guides in the vertical direction by a hydraulic cylinder.

The workpiece is placed on the table and based on the side left or right guide ruler and the front end stop. The side rulers are adjustable and allow you to adjust the size of the outer eyelet.

The end stop can be adjusted in the range of 0...50 mm to ensure the required tenon length. The workpiece is secured on the table with hydraulic clamps. A casing is installed in the upper part of the chip removal machine, which is connected to the exhaust network. On the left side of the frame there is a hydraulic panel on which hydraulic valves are mounted, safety valve and throttle 3 to change the speed of table movement.

The hydraulic drive of the machine ensures reciprocating movement of the table through the cycle: clamping the workpiece, working stroke of the table with clamped workpieces downward at a given feed rate, idle movement of the table with clamped workpieces upward at an increased constant speed, unfastening the workpiece.

The hydrokinematic diagram of the machine is shown in Fig. 114. When the electric motor of the hydraulic unit is turned on, oil from the vane pump NP through the strainer F and distributors P1 and P2 enters the hydraulic tank B of the machine.

In the initial (upper) position, the table is held by oil pressure on the piston of the C1 cylinder. The oil outlet from hydraulic cylinders C1 and C2 is locked in the middle position of hydraulic valves P1 and P2. When the electromagnets and distributors Pi and P2 are turned on simultaneously, the table and clamps occupy the original top position.

Rice. 1. Tenoning machine for box straight tenons 111PK-40: 1 - bed, 2 - hydraulic unit, 3 - throttle, 4 - milling shaft, 5 - table, 6 - guide ruler, 7 - end stop, 8 - hydraulic clamp, 9 - workpiece , 10 - electric motor, 11 - hydraulic cylinder

The working stroke of the table is carried out by turning on the electromagnet b of the distributor P2. In this case, the electromagnets of the distributors P1 and P2 are turned off - the workpieces are pressed. The pressure in the system increases, the pressure switch RD is triggered and turns on the electromagnet b of the distributor P1 - the working movement of the table occurs.

At the end of the working stroke, the table presses the limit switch pin, which turns off the electromagnet b of the distributor P1 and simultaneously turns on the electromagnet a of the same distributor. The table begins to move upward when electromagnet b of distributor P2 is turned on.

When the table reaches the top position, the limit switch is activated, which turns off electromagnet b of hydraulic distributor P2 and turns on electromagnet a of hydraulic distributor P2. The clamps release and the workpiece is released. The table turns out to be fixed in the upper position, since the oil in the C1 cylinder is locked by the middle position of the hydraulic valve spool P1.

In the event of an emergency power outage, the table and clamps are fixed (the table stops, the workpiece is pressed), since hydraulic valves P1 and P2 are automatically set to the middle position. To remove the workpiece from the cutting zone and detach it, it is necessary to raise the table to its original position by turning on electromagnet a of the hydraulic distributor P1 and electromagnet b of the hydraulic distributor P2.

The cycle is turned on by pressing the “Cycle” button located on the control panel. In Setup mode, you can move the table up and down and stop in these positions.

The pressure in the system is regulated by the safety valve KP and monitored by the pressure gauge MN. The working speed of the table is regulated by the throttle of the flow regulator RP.

Selecting the operating mode. The feed speed in the machine is determined depending on the type of wood, the width of the workpiece and the length of the tenon. In table Figure 6 shows the cutting modes when processing straight box tenons with a width of 8 mm at a wood moisture content of 10%.

When assigning modes, a short-term overload of the electric motor of the milling shaft of no more than 25% is allowed. When processing wedge tenons on hardwood parts, the feed speed should be no more than 4.5 m/min.

Rice. 2. Hydrokinematic diagram of a tenoning machine for straight box tenons: a, b - electromagnets, B - tank, NP - plate pump, F - filter, KP - safety valve, MN - pressure gauge, RP - flow regulator, PI, P2 - distributors, RD - pressure switch, Ts1, Ts2 - hydraulic cylinders, XX - idle speed, РХ - power stroke

Setting up machines. To process straight box tenons, a set of 25 cutters is used. The set mounted on the milling shaft must contain cutters of the same diameter, width B, equal to the width of the eye being produced. Deviation in the width of the cutter is allowed no more than 0.03 mm.

When processing wedge tenons, a set of two cutters with wedge teeth is used. The teeth of the cutters must have the same height and identical shape. It is not allowed to install cutters with chipped or blunt teeth on the spindle. The cutters on the quills must be securely fastened with nuts.

Before replacing the cutting tool, you must set the switch on the control panel to the “Adjustment” position. This eliminates the possibility of turning on the milling shaft drive motor.

To replace the tool, unscrew the special nut of the support bracket, move it along the spindle and rotate it 90°, ensuring free access to the tool from the end of the spindle. New tool installed in the following order. The side hinged bolts connecting the clamp to the table are moved to the upper position and securely secured to the upper casing. By pressing the “Start table down” button, set the table to its lowest position, after which the casing with clamps is tilted 90°, providing free access to the tool. Holding the spindle wrench, unscrew the left nut securing the cutter set.

A set of cutters for a straight box tenon consists of two quills connected to each other by a toothed coupling. First, remove the left quill with 12 cutters, and then the right one with 13 cutters.

When changing tools, you must follow safety regulations. The cutter set is removed and placed in a special box for subsequent transportation to the sharpening department of the workshop.

Both cutters for processing wedge tenons are installed in extreme positions relative to the spindle and side guides through spacer rings and a bushing. After installing the tool, secure the folding bracket with a special nut. The bracket is equipped with a lock that prevents the drive motor from being turned on, so you should pay attention to the correct interaction of the bracket with the blocking microswitch.

The table is returned to its original upper position by pressing the “Start table up” button. Then install in working position clamp The side guides of the ruler are adjusted depending on the width of the outer eye. The left and right rulers are adjusted so that two paired workpieces with straight tenons can be processed simultaneously. Adjustment of each ruler to the required size from the outer tenon is carried out with the appropriate screw.

The end stop is adjusted to the required length of the tenon by rotating the screw and then fixing it with a lock nut.

The hydraulic clamps are mounted on the table with two stands and hinged screws.

The amount of table travel is determined by the position of the microswitches installed on the frame. To check the correctness of their operation, switch the machine with the operating mode switch to the “Adjustment” mode and practice the movement of the table up and down.

Rotate the throttle handle to set the required operating speed. Before starting the machine, turn on the exhauster chip removal system.

To improve the quality of tenon milling and prevent chipping when the cutters come out of the wood, an additional support is used - a backing block or shield on which the workpiece is installed. On the first pass, spikes are formed at the end of the backing board. The end of the backing board, which constantly interacts with the cutters, wears out quickly, so it should be periodically rearranged or replaced with a new one.

Working on machines. The machine is started in an automatic cycle by alternately pressing the power buttons for the electric motor of the milling shaft and the hydraulic pump. The machine is operated by one worker. He takes a stack of planks, places them on the table and aligns them against the fence and the front end stop. After pressing the “Cycle” button, the boards are pressed to the table by an automatically operating clamp and the table makes a working and reverse stroke. In the original position of the part. are detached and the machine operator, turning them over 180°, again bases them in the machine for processing tenons at the other end with the same machine setting. After the second pass, the finished parts are stacked.

Having finished processing a batch of parts, the machine operator begins to tenon the mating planks, having previously moved the side guide ruler to the thickness of the tenon or using a second guide ruler for this.

To avoid defects, the boards entering the machine should not have wingedness, curvature, or non-perpendicularity of the ends to the edges and faces. During the processing process, the quality of the resulting studs is controlled with a tool or visually by trial assembly of the tenon joint of paired parts.

The thickness of the tenon and the width of the eye are measured with a caliper or other measuring instrument at points located at a distance of 1/4 of the length of the tenon from the bottom of the eye and the end face of the tenon. Check all the studs and lugs of this part.

In the process of making furniture and carpentry, the component parts are often connected to each other “tenon-to-tenon”. There are several types of tenon joints: dovetail, box, round and oval, allowing you to mount parts at the required angle or extend them. A tenon is a rather complex element to make, for which special equipment has been created - a tenon-cutting machine.

Types of tenoning machines

A wood tenoning machine is used to form tenons and lugs on parts of frames and drawers to connect them at an angle, as well as to form a mini-tenon necessary for the procedure of joining workpieces together. Such machines are quite common in furniture factories.

Two types of tenoning machines have been developed:

• frame tenoning machines
• box tenoning machines.

They differ in the type of spike produced.

According to the method of processing parts, tenoning woodworking machines are divided into:

• unilateral
• double sided

They will help to form a straight tenon, a rounded tenon or a dovetail tenon.

Single-sided tenoning devices are positional type machines. Their design assumes the presence of a desktop that performs a reciprocating movement. The workpiece is mounted on this table. After completing the first set of operations with the workpiece using the carriage, it returns back. And all the work done is repeated again, only now on the other side of the workpiece.

Double-sided tenoning devices are position-through type machines. In such machines, workpieces are fed without interruption using a chain conveyor and a clamping mechanism. In this case, processing is carried out on both sides simultaneously. The design of these devices has two identical columns, one of which moves along guides, with its help the machine is adjusted to a certain length of the part.

The cutting mechanism on tenoning machines is cutters, and to create a dovetail tenon they use end mills conical shape. The machine mills tenons and recesses for them (eyes) in the constituent parts of wooden structures.

Dovetail and box straight tenons are formed on special types machines that are produced for professional use at large enterprises. The resulting fastenings are highly reliable and guarantee long-term operation products.

Spikes are round and oval shape are formed on devices that have CNC and operate in automatic mode. CNC machines are capable of working with workpieces in any plane.

The most popular are tenon cutting machines for frame, door and window structures.

Main parameters

The main characteristics of tenoning machines include:

• maximum diameter of the workpiece being processed
• largest tenon width
• largest tenon diameter
• type of thorn
• spindle speed
• engine power level
• dimensions and weight.

The main requirement for a tenoning machine is high precision operations. Otherwise, the parts will not match each other and the connection will not work.

Tenoning machines are used:

• processing of calibrated panels, chipboards
• overtaking the perimeter door leaves, window frames
• floorboard treatment
• creation of parquet.

Some features of use:

• On large production conveyors, such machines are mounted on the ceiling. As an additional equipment, there are clamping devices that accept workpieces and scoring saws. The workpiece falls on the miter saws, and therefore is processed by two milling supports.
• the feed speed of the workpiece can be smoothly adjusted using a variator
• To ensure high-quality processing, the spindle speed must be 7000 rpm
• The length of the guide can be 2, 2.5 or 3 meters
• the design makes it possible to use several different instruments for wood processing
• the equipment can be additionally equipped with a pneumatic clamping mechanism and an extension work surface.

Box tenoning machines

Straight box tenons are created using both single-sided and tenoning machines

The spindle in such devices is in a horizontal position, and the box boards are stacked on the work table and fed in a vertical plane in the direction tangent to the circumference of the cutting system of such machines.

The device includes a frame, in the upper part of which there are bearings. They have a built-in spindle, which is connected through a pulley and a belt drive to electric motor. One of the three bearings in which the spindle is mounted must be removed during installation of the cutting tool. On the machine bed there are elements of the table feed hydraulic drive. The table is distinguished by a movable mounting on runners in the guides of the device. The control panel contains the electric motor starting equipment (push-button station and magnetic starter). The table moves vertically due to a hydraulic feed mechanism.

The job of double-sided box tenons is to create straight box tenons on both ends of the part at the same time.

The advantages of such devices:

• ease of control and adjustment, as well as automatic tool feeding. All this guarantees the maximum level of machine performance
• the device is capable of processing both parts of the dovetail joint separately or simultaneously
• The workpiece is fixed manually using pneumatic clamps
• all settings are controlled from the control panel
• Thanks to CNC, you can change the tenon pitch, number of grooves, tenon depth, workpiece dimensions, and feed speed.

The equipment can also be additionally equipped with a special shelf for storing workpieces. This is very helpful in the process of routing dovetails on curved and shaped drawers.

In the process of creating wooden windows and doors, the milling and tenoning machine is very popular. In this section we will tell you how to make a tenoning machine yourself.

Upon completion self-assembly, you will get a device that will not need to be reconfigured, because it will be created specifically for working with tenon cutting. Before you begin assembly, you need to buy two spindles. The design diagram of the carriage can be easily found on the Internet. If you are not satisfied with it, you can always make your additions.

Often in general design When using a tenon cutting machine, the craftsmen change the length of the guide bar upward. This means the load is growing. For this reason, you can refuse to use square pipe. It can be replaced with an I-beam, to the flanges of which you need to weld the corners.

Experienced craftsmen do not recommend using a standard carriage. There must be two in the carriage steel angle 6.3 cm each, eight 301 bearings, as well as car bolts (L50) and washers for them. It is worth cutting out the fasteners in the shape of the letter “T” from an I-beam, and screwing a table with a guide and a clamp to them.

We emphasize that the clamp must be manufactured in a factory and you need to buy it in specialty store. The presence of a table is necessary in order to obtain additional rigidity. The corners need to be tied diagonally. At the same time, although the carriage turns out to be quite rigid, it moves easily and smoothly. It can also be mounted on other types of devices.

The previously purchased spindles are attached to a beam 1.8 meters long. The height of the cutters is selected using bushings, washers and a slotting machine. Be sure to note that this work must be carried out with the hood on if you are working in an enclosed area. After all, during the work process a large amount of dust is generated. In addition, the cutters need to be covered with a barrier, which can be created from three boards.

A homemade machine, of course, will be quite dusty and noisy, but it will save you time and money.

Comparative characteristics tenoning machines

Name	Parameter value
		ШД10-8	ШД16-8
Maximum tenon length, mm
Maximum depth of lugs, mm
Minimum thickness, eye width, mm
Minimum distance between shoulders, mm
Largest dimensions of the workpiece being processed, mm
Feed rate maximum, m/min minimum, m/min
Saw diameter, mm
Saw rotation speed, rpm
Electrode power, kW
Cutting speed, m/s when sawing when milling
Tenoning cutters diameter, mm rotation speed rpm
Lug cutters diameter, mm electric motor power, kW rotation speed, rpm rotation angle, degrees
Feed drive
Rotation speed, rpm
Drive for moving the movable rack
Rotation speed, rpm
Electric motor power, kW
Total power of the machine, kW
Conveyor working surface height, mm
Specific energy intensity
Specific metal consumption
Name	Parameter value
	Designed machine KP13-97	Machine of similar design
		ШД10-8	ШД16-8
Dimensions of the machine (approximately for the one being designed), mm

For a long time, tenon joints have been used when assembling drawers, doors, windows and other frame structures. To accurately and quickly obtain such complex elements in wooden structures, a wood tenoning machine is used.

This equipment is used both in entrepreneurial activity, and in large-scale production. It is indispensable in the manufacture of furniture, as well as in house construction and woodworking enterprises.

Types of tenoning machines

A tenon saw is a type of woodworking machine. There are samples of both imported and domestic production on the market. The fixing elements on it can be processed for subsequent connection of products at an angle, as well as for their merging (dovetail folds are used).

Machines for milling tenons are divided into frame machines and box machines according to their intended purpose.

In this case, frame units are:

• one-sided In one pass, the tenons are processed on one side of the workpiece;
• two-way automated. The design of a tenoning machine involves placing supports on two columns and, accordingly, processing the workpiece on both sides.

Naturally, the productivity of double-sided tenoning machines is much higher than their analogues. There are several types of units, which differ in length, and they come in 2, 2.5, and 3 meters.

The cutting tools for them are cross-cut saws and cutters (disc and end) for processing straight tenons, eyes on frames and frames different designs made of wood.

The formation of box and dovetail tenons is done on specialized machines, mainly in large-scale and mass production. At the same time, there are two types of dovetail fixation: with rounded and sharp corners.

The first category is produced on multi-spindle tenoning machines. Such shaped protrusions are processed simultaneously on the mating surfaces using modular cutters. It is this connection that guarantees the durability and reliability of the fixing unit.

When producing the most complex oval dowels (small tenons) and those with a round shape, automatic tenoning machines with numerical control are used.

Specifications

The operator’s functions when working on an automatic machine are reduced to loading and turning workpieces, starting or stopping the cycle. Important indicators tenoning units are:

• largest peg size;
• the smallest thickness;
• groove height;
• width;
• maximum workpiece size;
• spindle speed;
• engine power.

In addition to the characteristics for classifying the machine, the parameters of the cutting tool are indicated: saw diameter, type and size of cutter.

Often on large production lines such equipment is installed to the ceiling. The machines are additionally fixed with clamping devices, where the workpieces are processed by scoring saws, followed by the formation of tenons on milling supports.

The feed is adjusted smoothly using a variator. To create a high-quality surface of the mating elements, the spindle speed should be about 700 rpm.

Operating principle

When forming pegs, a sawing and milling procedure is usually used. An appropriate cutting tool is used to obtain the tenon joint surfaces.

Attention! Whatever the shape of the tenons, the initial operation is to trim the workpiece.

For the most common models that use milling during processing, the machines are equipped with four spindles - three milling and one sawing. One or more workpieces can be loaded onto the carriage table, and they are aligned with their edges along the ruler and their ends along the stop bar.

The tenon is formed as a result of end milling. When the cutting tool comes out, chips may appear on the edges, so to prevent them, a support block is mounted on the ruler, and some machines also provide for the application of glue to the surface being processed.

After turning on the feed mechanism, the product is automatically fixed due to the side and top hydraulic clamps. The carriage with the workpiece begins to move at a certain speed along two guides relative to cutting tools.

In this case, during the movement of the carriage, a spike of the desired configuration is formed on the structure, then the device, having reached the stop (limit switch), returns to its original position. This is where the replacement takes place. finished product onto the workpiece, and the cycle repeats again.

If the machine is double-sided, the process of forming tenons occurs on both sides of the workpiece.

Homemade tenoning machine

Today there are all opportunities for entrepreneurial activity, while many are engaged in the manufacture of furniture, wooden doors and windows, where connecting spikes are indispensable when assembling the product. And since tenon cutting machines are not cheap, at first a homemade unit is quite suitable for obtaining fixing elements.

It is easy to make on your own, which will save a lot of money when organizing production. Moreover, there are different options for the manufacture of such machines, where the base element can be a stationary engine, an angle grinder, a jigsaw and even an electric drill.

Let's consider making a do-it-yourself tenoning machine based on a grinder with a disk cutter positioned in a horizontal position.

As in a factory machine, here, in addition to the engine and cutting tool, there are two components:

• bed;
• tabletop.

The bed must be strong and stable, since it is the base part of the unit on which the device for fastening the workpiece and the grinder with the cutter are installed. This component of the tenoning machine can vary in design and be manufactured without drawings. For example, it can be made from metal corners, and a sheet of chipboard can be fixed on them.

The size of the tabletop must correspond to the intended workpiece. It also contains clamps and a control ruler.

The bed guides must be strictly perpendicular to the movement of the tabletop during milling connecting elements. The quality of the connection between the studs and lugs depends on this.

Machine assembly

The location of the shaft exit is determined on the table surface and a hole of a slightly larger diameter is made. The grinder is fixed with clamps, and you need to make sure that the heads of the bolts are flush with the plane of the tabletop.

Disc cutters are used as cutting tools. In this case, one cutter is used to select the eye and two cutting discs if it is necessary to process the tenon. Accordingly, the distance between the cutters is equal to the width of the groove.

Important! If two disc cutters are used, the fit on the grinder should be through an adapter with keyways.

With this assembly, the process of milling an eye or tenon occurs due to the movement of the workpiece. To do this, it is attached to the tabletop with clamps and then manually moves along the frame guides to the rotating cutter. In this case, the dimensions of the stud and eye are achieved due to the stops and the thickness of the washer between the discs.

The use of such a homemade tenon-cutting unit makes it possible to obtain proportionate tenons and eyes, which significantly increases labor productivity.

24.05.2015

According to the classification, tenoning machines for straight tenons are divided into single-sided and double-sided. On single-sided machines, in one working cycle, tenons are obtained by milling at one end of the workpiece, and on double-sided machines, tenons are simultaneously milled at both ends of the workpiece.
Milling of straight tenons in both cases is carried out with a set of disk cutters or a set of cutters in the form of hooks. When using these cutters, the workpiece can be fed to the cutting tool in a radial (along the radius of the cutter) or tangential (tangent to the cutting circle) direction.
The technological scheme for processing a tenon (Fig. 147) shows that with radial feed, the bottom of the eye cavity is concave with a radius of curvature r and an arrow of curvature

In practice, y does not exceed 1 mm and the concavity does not affect the assembly technology. In this case, single-sided machines with manual feed are used, on which only one workpiece can be processed at a time.
When the workpiece is fed tangentially, the bottom of the cavity is straight (see Fig. 147). In this case, you can mill workpieces in batches from one and both ends at the same time. When the workpiece is fed radially, the movement is intermittent, and when the workpiece is fed tangentially, it is continuous. The kinematics of chip formation is also different.
Currently, tenoning machines with radial feed are not available. Previously produced ShP-1 machines are now used only in auxiliary industries.

Machines with tangential feed received widespread. Moscow plant of woodworking machines and automatic lines serially produces one-sided tenoning machine ShPA-40 (Fig. 148, a). The main components of the machine are: a cast-iron bed 1, on which a horizontal milling shaft 2 is mounted, driven by an electric motor 6 through a V-belt, and a cast-iron movable table 5 with two hydraulic membrane clamps 7 for securing the workpieces during milling. The bed has vertical guides for the table.
The lower part of the table is rigidly attached to the hydraulic cylinder rod 4, which lifts the table vertically relative to the milling shaft. A movable ruler 8 is fixed on the upper plane of the table, to which the workpieces are pressed. The ruler on the table is installed perpendicular to the axis of the milling shaft, and it can move along the axis when adjusting to the desired width of the shoulder of the first tenon.
The clamps are placed on a horizontal crossbar, which is attached to the table through racks. This design allows them to move in horizontal and vertical planes and be installed depending on the width and thickness of the workpiece being processed. Workplace the clamp is fixed with special clamping devices. A guard 3 is installed on the milling shaft. It is mounted on three bearings, of which the third is an end bearing and is removable. This allows disc cutters to be mounted on a horizontal shaft.
In Fig. 148, 6 shows the hydraulic diagram of the machine. Oil from tank 1 through filter 2 is supplied by pump 3 to the pressure line. The pressure line is connected by oil lines to the hydraulic cylinders of the clamps 11, the control valve 5, the reversing spool 5 and the safety valve 4. When the carriage is loaded with workpieces, there is no oil pressure in the pressure line, since the upper cavity of the safety valve is connected to the drain through the unloading spool 9 and the control valve 8 highway.
The table is fed by turning the control valve handle 8 clockwise. This connects the upper cavity of spool 5 and spool 9 to the pressure line, and the lower cavity of spool 5 to the drain. In the pressure line
the pressure rises to the value set on valve 4, the pressure value is indicated by pressure gauge 10. At this time, the clamping cylinders 11 are activated, and the clamps are secured to the workpiece table. At the same time, the piston of the spool 5 is lowered under the influence of oil pressure, connecting the lower cavity of the hydraulic cylinder 12 with the pressure line, and the upper cavity with the drain line. The hydraulic cylinder rod, together with the table and fixed workpieces, rises up into the cutting zone of the cutters. In the uppermost position of the table, the rod 13 attached to the table turns the control valve 8 to its original position. After the corresponding movement of the spool pistons, oil from the line enters the upper cavity of the hydraulic cylinder 12, and the table will begin to move down. The safety valve maintains pressure at this time, since in the unloading spool 9, under the action of the spring, the piston is in the upper position, and the tube connecting the safety valve to this spool is insulated. When the table reaches its lower starting position, the rod 13 acts on the piston of the spool 9, and it moves to its extreme position, at which it connects the safety valve with the drain line. The pressure in the network drops, the pistons of the clamping hydraulic cylinders rise under the action of springs, releasing the workpiece from the clamp, and the cycle repeats. The feed speed is controlled by throttle 5 and 7, and the speed idle speed does not change.

The domestic industry also produces double-sided tenoning box machines Sh2PA and Sh2PA-2. The latest model is a variation or modification of the Sh2PA machine. It differs only in the elongated bed, which allows you to process longer workpieces. This machine is the most modern, pass-through type, equipped with a conveyor feed mechanism and magazine loading, it is highly productive and can be used for mass production of box parts and integrated into automatic lines.
The design of this machine provides for basing the workpieces on the guide traverses only with a wide face. Tenoning is carried out with vertical movement of the milling spindles from top to bottom, the workpiece is stopped and the conveyor is continuously moving.
In Fig. 149 shows the technological diagram of the Sh2PA machine. The workpiece 1 from the store 2 pushers 6 (conveyor chains 4) moves along the base beams 3. During processing with saw blades 7, the workpieces are continuously pressed to the base planes by a conveyor clamp 5. The conveyor chain is equipped with hinged pushers 6. To switch the pushers into the working position and turn them off The guide lines 9 serve as guides, on which the pushers 6 rest with the shank and slide along them when the chains move. After the shank leaves the guide, the pusher overturns, leaving the workpiece 8 alone. When the workpiece is stationary, the support 10 with a set of cutters 11 moves vertically along the guides 12. In the process of lowering the milling tool, tenons are milled. The working and idle movement of the caliper 10 is transmitted from the drive shaft 13 by a helical gear 14.
The kinematic diagram of the Sh2PA-2 machine is shown in Fig. 150. The conveyor feed mechanism is driven by electric motor 1 through spur gears and worm gear 2. Vertical movement milling supports are carried out using lever mechanisms 3 connected to cylindrical cams 4. Cams 4 along the generatrix of the cylinder have a profile groove into which the pin of the lever system fits. The profile groove of the cam is made in such a way that it, together with the levers, copies the up and down movement of the caliper.
The profile cam receives movement from the main drive shaft by the chain conveyor 4a.
To the original (upper) position milling head returns with the same cam and two extension springs 5 ​​mounted on the head support.

The supports are equipped with chip receivers that are connected to a pneumatic transport system. To press the workpieces to the conveyor guides, there are clamping devices 13 and 11 (right and left), located above the conveyor chains 17. The clamping device moves in horizontal and vertical directions using a handle 12. The clamping crossbar is equipped with freely mounted rollers 9 with two grooves for V-belts . The saw spindle 10 is an MD electric motor, at the end of which a saw is mounted. The supports of these spindles are equipped with mechanisms for vertical 20 and horizontal 21 movements. The spindle is installed according to a graduated scale.
Milling spindle 6 is a horizontal shaft mounted on three ball bearings to a caliper, which moves along the vertical guides of the stand.
The drive of the milling support is from the electric motor 7 through a V-belt drive 8. The electric motor is mounted on a swinging sub-motor plate. From the magazine 22, the workpieces are captured by stops 16 of the conveyor chains 17 and fed to the cutting heads.
Saw supports 19 are installed first along the way, forming the workpiece exactly to its length. Then the workpiece is fed into the action zone of the milling spindles 6.
In the milling zone, the workpiece stops, as the pushing cam 16 of the chain leaves the guide 23 and rotates around the hinge axis, leaving the engagement zone with the workpiece. At this moment milling spindles are lowered and the tenons are cut, then the spindles rise to their original position and at this moment another workpiece comes up, pushes out the processed one, and itself stops in the cutting zone. Then the cycle repeats. The place where the workpiece stops in the milling zone is regulated by mechanism 18.
The movable cabinet (right) moves along the frame from an electric motor 14 with a power of 0.5 kW, through a single-thread worm gearbox 15 and a spur gear connected to a rack 23 mounted on the side wall of the machine bed. Precise installation of the right stand and cutting tools along the length of the part is carried out by handle 24, brought to the front of the machine; The handle shaft is connected to the gearbox worm through a friction clutch.