Gearing friction gearing

General Considerations. Friction gears depend for their driving action upon the friction of the driving wheel, or driver, against its mate, or follower. The friction surface of a driver should be of a comparatively soft material, such as wood, fiber, leather, paper, or rubber, while that of the follower is usually made of cast iron. This arrangement insures the maintenance of the correct shape of the friction surfaces; whereas if the follower is of the softer material its surface might be injured and eventually ruined when starting under load or when an excessive load has brought it to a standstill

Friction gears are used for light and medium powers in machinery, which is frequently started and stopped, also where provision for a change of speed of the driven shaft or a reversed motion is necessary. Their advantages are flexibility and noiselessness.

The disadvantages of friction gears are the thrust on the bearings and slippage, resulting in a comparatively low efficiency. However, by using metal-to-metal contact surfaces and ball or roller bearings, these objections are partially eliminated in some recent designs.

The driving capacity of friction gears is a function of the coeffi­cient of friction between the surfaces in contact and of the pressure, which holds them in contact. This pressure is limited by the ability of the softer surface to endure it without injury

Toothed bevel gearing

General Considerations. Bevel gears are used to connect two shafts whose axes intersect each other. Two types of bevel gearing are in general use, straight-tooth gears and spiral-tooth gears. In the straight-tooth bevel gears called straight bevel gears, the elements of the teeth converge to a common point, called the apex, which is the point of intersection of the gear axes. The form of tooth used for bevel gears is the involute Spiral bevel gears are made either with curved teeth, or with straight teeth. Spiral bevel gears compared with straight bevel gears much as helical gears on parallel shafts are compared with straight-tooth spur gears. Their advantages are smoother tooth engagement, quiet operation, greater strength, and higher permissible velocities.

Bevel gears are not interchangeable and are designed in pairs. In the majority of cases the axes of the shafts form a right angle, but they may intersect at any desired angle.

TEXT 17

Removable excavating and loading implements

1.The using of front-end clamshell bucket which in addition to performance of the loading/unloading operation, provides for execution of the dozing work as well as for loading of the logs, stones etc.

Bucket capacity ……………………….0,63(0,8) m3

Dumping height ……………………………….2,7 m

2. On customer’s request the excavator can be equipped with Receiver and Welding Set EU-10 (E4-63), what permit to use it during the repair works without separate welding-set and compressor.

Rated voltage ………………………………..….28 V

Rated current …………………………………..360 A

Electrode diameter …………………………...3-5 mm

3.The UP-Rotor uses construction for cleaning the ground from stumps, stones etc.

Clamp diameter ……………………………...500 mm

4. Ripping tooth used for the rip of the ground.

Ripping radius on the stage of standing………..…5 m

Tooth lip cutting force …………………....16000 kg f

5. Boring equipment can utilize the excavator for the installation of fences, clinks for electric and telephone pillars, plant trees etc.

Boring depth ………………………………...……2 m

Hole diameter ….………………………..150-450 mm

6. Hydraulic hammer provides for crushing and breaking of concrete and cement surfaces and fully exclude the utilization of compressor with pneumatic pick and after the installation of one of the removable working part of hydraulic hammer (wedge, spear) you can do another kind of works such as ground ramming for foundation.

Individual impact energy ………………………1,22 kj

Frequency of impacts ……………………..140 per min

7. Сhanging of excavator equipment to the lift permits to held works by 2 workers at the height …………………………7 m

8. Telescopic handle enlarges the digging depth and unloading height.

Dumping height ………………………………….4,4 m

Digging depth ……………………………………5,4 m

9. The Loading Clamp is using for loading/unloading operations with the loads with large dimensions-logs, pipes with big diameter and so on.

Weight ………………………………………….800 kg

Lifting height ………………………………….....2,7 m

10. Front-end bucket can be replace by Concrete mixer. It permits to utilize the excavator during the solvent-concrete operations.

Capacity …………………………………………150 lit

Concrete mix feeding height …………………….2,7 m