Push rollers

The rotating rollers are mounted at the front of the paver, and they are in contact with the tyres of the delivery truck and used to push the delivery truck. 

---

The basic components of a tractor unit are the following hopper, push rollers, conveyor, flow control gates, side arms, augers and automations and control panel. 

Pellet Mills Pellet mills operate on the principle shown in Fig. 20-92. Moist, plastic feed is pushed through holes in dies of various shapes. The friction of the material in the die holes supplies the resistance necessary for compaction. Adjustable knives shear the rodlike extrudates into pellets of the desired length. Although several designs are in use, the most commonly used pellet mills operate by applying power to the die and rotating it around a freely turning roller with Fixed horizontal or vertical axis. 

Pultrusion is also used to make structural shapes from composite materials. The incoming material is generally unidirectional and must be pulled through the pultrusion die because the uncured composite material is entirely too flexible to push (as in extrusion processes). The incoming material can be preshaped by various guides and rollers as in Figure 1-18. 

The California roller technique, which also was used to generate some of the data in this study, consists of placing a defined-size piece of cloth material onto the treated turf, covering the cloth with a plastic sheet, and then rolling over the plastic and cloth sheets with a roller that contains 25 lb of lead shot. Typically, the roller is pushed back and forth over the sheets 10 times. The cloth is then extracted and analyzed for residues. 

Timken EP test—measure of the extreme-pressure properties of a lubricating oil (see EP oil). The test utilizes a Timken machine, which consists of a stationary block pushed upward, by means of a lever arm system, against the rotating outer race of a roller bearing, which is lubricated by the product under test. The test continues under increasing load (pressure) until a measurable wear scar is formed on the block. Timken OK load is the heaviest load that a lubricant can withstand before the block is scored (see scoring). 

Fig. 4.1. Scrapers used to remove cells from surfaces. The upper scraper is used to scrape cells from inside roller bottles. The blade folds forwards allowing it to pass through the narrow neck. By pushing against the bottom of the bottle the blade opens as shown and the shape of the arm prevents further movement. The middle scraper is a rubber policeman fitted to a bent glass rod. It is used for scraping cells from smaller bottles. The lower scraper is used for dishes where the edges of the cut silicone bung allow cells to be removed efficiently from the corners of the dish.

Dehont et al. provided a simplified approach to roller compaction theory. They described that powder granules move through stages in the feed area. The material is drawn into the gap by rubbing against the roll surfaces. The densification that occurs in this area is particle rearrangement. At this stage, the speed of the powder is slower than the peripheral speed of the rollers. Fig. 1 represents compactor rolls in the horizontal plane powder is pushed vertically downward into the compaction area. 

The first type of roller found in most laser printers is the feed roller, or paper pickup roller (Figure 7.6). This D-shaped roller, when activated, rotates against the paper and pushes one sheet into the printer. This roller works in conjunction with a special rubber pad to prevent more than one sheet from being fed into the printer at a time. 

In the final step, the fusing step, the toner image is made permanent. The registration rollers push the paper toward the fuser rollers. Once the fuser grabs the paper, the registration rollers push for only a short time more. The fuser is now in control of moving the paper. 

Raisin Seeder.—The elements for one device of this kind are a cylinder mounted with closely spaced pins placed radially. The spacing of the pins is smaller than any thickness of the seed. The other elements of the seeder are a hopper in contact with the pin mounted cylinder, means for squeezing the raisin into the pins of the cylinder as by a flexible or flexibly mounted roller or rollers. Since the pins are so closely mounted that the seed cannot be squeezed in between them only the meat of the raisin is pushed into the interstices and the seeds project above the pin cylinder. Means are provided for removing the seed as by a scraper or toothed roller and finally means for removing the meats by a sawtoothed scraper. The operation of the household cherry stoner is too familiar to need description. 

Pan mullers are the modern industrial equivalent of the traditional mortar and pestle. Typical mullers have two broad wheels (Ml and M2) on an axle (Fig. 18-54). The mixer rotates about the approximate midpoint of the axle, so that the wheels both rotate and skid over the bottom of the mixing chamber (A). Plow blades (PI and P2), which rotate with the mixer, push material from the center (T) and walls (C) of the mixing chamber into the path of the rollers. The mixing action combines both crushing and shearing to break lumps or agglomerates and evenly distribute moisture. 

---