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Driven crank or eccentric and friction presses.
In these presses, the rotational motion created by an electric motor is converted into translational motion of the working parts using crank shafts, which is why such presses are called crank presses. However, according to the method of connecting the crank shaft to the connecting rod, eccentric and crank presses are distinguished.
Rice. 23. Schematic diagram eccentric (a) and crank (b) presses: 1 - slider, 2 - axle, 3 - connecting rod, 4 - eccentric disk, 5 - cage, 6 - shaft, 7 - engagement clutch, 8 - flywheel, 9 - electric motor, 10 - side slider, 11 - bearings, 12 — crankshaft, 13 — gear transmission, 14 — V-belt transmission
In eccentric presses (Fig. 23, a), an eccentric disk 4 is mounted on the crank located at the end of the main shaft 6. The eccentric is enclosed in a cage 5 connected to the connecting rod 3 (or made integral with the connecting rod).
When the shaft rotates, the eccentric moves the connecting rod down and up, as a result of which the slider 1 also moves. At the lower end of the connecting rod there is a ball heel (axis) 2, the hinge joint created by which ensures the movement of the connecting rod, repeating the movement of the crank or eccentric. To adjust the initial (closed) height of the slider, the connecting rod is equipped with a screw, with the help of which the length of the connecting rod and, consequently, the distance between the slider and the press table are changed. The main shaft receives rotation from the electric motor 9 through a belt drive and a flywheel pulley 8, into which the engagement clutch 7 (usually a cam or friction clutch) is built-in. A control handle or pedal is connected to this clutch through levers, with the help of which the working stroke of the press is carried out. Eccentric presses are used for trimming, sheet and volumetric stamping
small parts
The press is driven from an electric motor 9 through a V-belt 14 and a gear 13 transmission. The side slider 10 is driven by an eccentric mounted at the end of the crankshaft. Thus, the press consists of two presses: crank and eccentric.
If the main slider on the press is used to trim the flash, then the side slider is used to perform the stitching, or vice versa.
Pressing is one of the most common types of pressure processing of materials. The pressing process involves changing the shape of the workpiece being processed by applying great force to it through a deformation tool. Pressing is also used to compact materials, squeeze out liquid, chop and cut materials.
- According to their design, presses are divided into two main types:
- Mechanical
greater force, the magnitude of which depends on the liquid filling the cylinders and the ratio of their diameters. As a rule, water or oil is used as a working fluid in hydraulic presses. This is due to their low compressibility, that is, their tendency to maintain a constant volume when exposed to high pressure. Main nodes hydraulic press
: frame (usually column type), movable cross member, main (working) and return cylinders. The designs of powerful presses include a hydraulic cylinder that balances the movable cross member. The principle of operation of a hydraulic press is that under the pressure of the liquid, which is the carrier of energy (the working fluid), the plunger is pushed out of the main cylinder, moves the movable cross member with the striker mounted on it and, after resting on the workpiece located on the table, plastically deforms it. In a mechanical press, the deformation of the workpiece occurs due to the reciprocating movement of the slider driven by. The main components of a mechanical press are: a steel or cast iron frame, a connecting rod, and a movable cross member (slider). An eccentric press is a mechanical press that uses an eccentric to move the ram instead of a crankshaft.
The full range of sheet metal processing machines is in the corresponding section
Considered one of the most common in production technological processes. It is the processing of material using pressure. The essence of the process is to push the workpiece through the hole in the matrix. Pressing is used to change the shape of a workpiece, cutting and compacting materials, squeezing out liquid, forging and stamping, etc. To process materials by pressure, a special mechanism called a press is used. One of the common types is eccentric press.
- This is a machine that uses an eccentric
- The stroke of the slider can be easily adjusted
- can be single-post or double-post
Design and principle of operation of the equipment
is a mechanical machine in which an eccentric is used to move the slide. Other types of pressing equipment use a crankshaft. Principle of operation machine is as follows: the workpiece is placed in the form closed type, which is pressed through the hole of the matrix. The shape and cross-sectional size of the part of the workpiece that is extruded are the same as those on the die. To press the workpiece, buffer devices are used, attached to the lower zone of the pressing equipment. They can be made using rubber and springs, as well as pneumatic, hydraulic and air-hydraulic.MÜLLER Eccentric press
Features and types
Main honors An eccentric press from a crank press, for example, is the ability to easily adjust the stroke of the slider by turning the sleeve associated with the upper head of the connecting rod, which is located on the eccentric of the shaft. As practice shows, during the technological pressing process the connecting rod experiences heavy loads, which can lead to equipment breakdown, therefore a safety washer is used to protect the connecting rod mechanism. It is placed under the end of the cylindrical thickening or the bearing of the ball head. If the press is overloaded, the safety washer can be quickly replaced.There are single-post and double-post. For the former, the connecting rod is located at the cantilever end of the working shaft, and for the latter, in the middle of the crankshaft supports.
Who produces? Companies such as: RASTER (Germany), HEILBRONN (Germany), SANGIACOMO (Italy), KOMATSU (Japan), etc. When choosing eccentric press you should pay attention to it specifications: working force, distances between the work table and the slider, between the slider and the intermediate plate, stroke, stroke adjustment, table clamping surface, reach to the middle of the slider, number of feeds, etc. This is very useful device
, which is useful for those who often encounter issues such as pressing out and pressing in various bushings and bearings.
Main materials used in assembly.
Channel 80mm, length 350-400mm.
Profile 40X40mm, length 1m.
Rod 12mm, 300mm long.
Tools.
Welding machine.
Bulgarian, wheels.
The racks are made of a 40X40mm profile, the height of these blanks is 350mm, the width at the outer edges is 270mm, so that there is 110mm between them.
Now Ivan will weld these racks to the base of the frame, and then show the next stage of work.
I welded the guide posts to the channel, then drilled 12mm holes.
A rod is placed in these holes.
An eccentric will be put on the rod. This is how it will work.
hand press
The stud is threaded on both sides.
On one side of the rod the author welds the nut tightly. I welded a 12mm nut on the outside of the rack, this seat
for the second side of the bar. Between the eccentric and the racks I put two bushings, from jet thrust
from a Lada.
Here is the cut piece.
Next, the author wants to strengthen this structure; he will weld spacers. This bushing will be welded to this crossbar and to the posts.
It is necessary to scald well to obtain a strong, monolithic structure.
Next, we will install the moving rod feed mechanism itself.
Reinforcements are installed and welded.
Now he will weld such a crescent to the movable rod.
The crescent will be welded at this point.
And the rod will move inside the bushing.
The press mechanism will work according to the following principle. The crescent will be in this position; it is clearly adjacent to the eccentric. When the eccentric is turned, the crescent will move down, putting pressure on the rod. This creates a pressing effect.
Also, the fixed bushing must be secured to the frame itself. I welded the guide bushing to the profile.
It will be attached to the frame like this. Also, the crescent-rod design will have a small gap so that the eccentric has a working stroke.
This side also needs to be strengthened, because this is a weak point and shouldn’t exist.
After this, the author welded the guide bushing to the frame.
And you can already experiment a little with this press.
Ivan will try to press the 307th bearing into such a housing.
Installs the housing, inserts the bearing, and inserts the plate to evenly distribute the pressing force.
Displays the crescent moon correct position.
And lowers the eccentric lever.
The press coped with its task. I pressed such a large bearing flush.
Without any damage, clearly, quickly, and effectively.
Now he will try the next, smaller one.
That's it, the roller is pressed.
This pressing method allows you to carefully and without damaging the bearing press it into the housing.
If you use a hammer or any hard objects to drive the bearing into the housing, it can be damaged. Usually the bearing race itself is damaged, and such difficulties can occur.
Therefore, it is much better to do it on the press. This is a good device - an eccentric press.
Of course, it has its flaws.
It is necessary to make a guide so that the rod with the crescent does not rotate.
And also slightly strengthen the rod mounting unit here.
Also install the return spring on the rod itself, between it and the bushing. This is necessary so that the rod rises automatically.
This press can also be used to solve other problems. For example, for punching holes, bending at an angle, and many other processes.
This pin is made of ordinary steel 3, from ordinary rolled metal. Of course, under such loads, it won’t last long. Naturally, it needs to be made from stronger steel.
