Lesson 12Lesson 12

Lathes Lathes

Lathes are machine tools designed primarily to do turning, facing, and boring. Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the workpiece. Consequently, more lathes of various types are used in manufacturing than any other machine tool

Turning n.镟制 [ 车削 ] 工艺The shaping of metal or wood on a lathechipless ~ 无屑车削contour ~ 轮廓车削copy ~ 仿形车削Facing Facing nn. . 端面车削Boring n. 镗 [ 钻 ]孔Facility n.容易 , 简易 , 便利设施 , 设备 , 工具reaming n. 铰孔versatility n.多功能性Versatile adj.通用的 , 万能的， 多面手的diversity n.差异 , 多样性biological diversity

The essential components of a lathe are the bed, headstock assembly, tailstock assembly, carriage assembly, and the leadscrew and feed rod.

headstock 主轴箱 spindleheadtailstock 尾架 ,尾座 , 顶针座Carriage 溜板箱车 ( 刀）架 , 拖板lead screw 丝杠导螺杆

1 Spindle box2 Feed box3 Saddle

4 Tool slide 5 Tailstock 6 Lead screw supporter

7 Feed box 8 Feed box 9 Cross slide

The bed is the backbone of a lathe. It usually is made of well-normalized or aged gray or nodular cast iron and provides a heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets.

nodular cast iron球墨铸铁Longitudinal adj. 经度的 , 纵向的

They are precision-machined to assure accuracy of alignment. On most modern lathes the ways are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.

Alignment 列队 , 成直线 , 校直 调正 , 调准 , 定线Abrasion n. 磨损

The headstock is mounted in a fixed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the work at various speeds. Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears --similar to a truck transmission--through which the spindle can be rotated at a number of speeds.

hollow spindle 空心 ( 主 ) 轴

Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modem lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.

Geometric ratio [ 数 ] 等比级数~ progressionmerely adv.仅仅 , 只 , 不过

Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of this hole is an important dimension of a lathe because it determines the maximum size of bar stock that can be machined when the material must be fed through spindle.

dependent adj.依靠的 , 依赖的 , 由 ... 决定的

The tailstock assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location. An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the tailstock and headstock spindles.

thereon adv.在那上面 , 在其上 , ... 之后立即transversely adv. 横着 , 横切地 , 横断地

The third major component of the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76 mm (2 to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.

tailstock quill尾架顶心套筒quill 套筒轴 , 主轴 , 钻轴 , 滚针

The size of a lathe is designated by two dimensions.The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways. The

second size dimension is

the maximum distance

between centers.

designate vt.指明 , 任命 , 指派表示swing v.摇摆 , 摆动 , 旋转回转

φ400

Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm ( 12 to 24 inches) swing and from 610 to 1 219 mm (24 to 48 inches) center distances, but swings up to 1 270 mm (50 inches) and center distances up to 3 658 mm ( 12 feet) are not uncommon.

engine lathe普通车床compound rest 复式刀架 ( 车床 ) 小刀架

Engine:1, A machine that converts energy into mechanical force or motion.2, A mechanical appliance, instrument, or tool.

Most have chip pans and a built-in coolant circulating system. Smaller engine lathes---with swings usually not over 330 mm ( 13 inches)--also are available in bench type, designed for the bed to be mounted on a bench or cabinet.

 

Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the workpiece, they are not suitable for quantity production. Often the actual chip-production time is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply.

Quantity production大量生产 , 成批生产

However, much of the operator's time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.

repetitious adj. 重复的turret lathe 六角车床turret n.小塔 , 塔楼 , 炮塔

Match the components’ name with the numbers in the figure and translate them into Chinese

Spindle boxFeed box

Tool slide Tailstock

Cross slideLead screw supporter

Power requirements and bale characteristics for a fixed and a variable chamber baler

A variable-chamber baler (VCB) and a fixed-chamber baler (FCB) were compared with respect to power requirements, field capacity, and bale mass. The fixed-chamber baler was operated with and without a coarse cutting mechanism (FCB/C and FCB, respectively). Average PTO power requirements were similar (10 to 15 kW) but peak power requirements were considerably greater with the FCB (38 kW) and the FCB/C (42 kW) than with the VCB (15 kW). The VCB had a material flow of 4.1 tonne of dry matter (DM) per hour (t/h) compared to 4.8 and 4.6 t/h with the FCB and FCB/C respectively. Bale dry matter mass was not affected by baler type nor by cutting and averaged 263 kg for a standard 1.22 m wide by 1.22 m diameter bale. Bale dry matter density varied, however, between 152 and 192 kg/m3 because of variations in material flow and moisture. Forage chopped with the FCB/C had an average length of cut of 150 mm.

Keywords: forage, round bales, power, mass, density, chop length

A software package for analyzing the costs of A software package for analyzing the costs of operating a mechanical wild blueberry harvesteroperating a mechanical wild blueberry harvester

Operating cost analysis software was developed for a mechanical wild blueberry harvesting operation. It allows growers and harvester owners to estimate total annual operating costs and operation component costs. Costs can also be calculated on a per hour and per pound harvested basis. User defined variable data allow for the calculations to be tailored ( 剪裁 , 缝制 ( 衣服 ), 适应 , 适合 )to a specific operation or to predict future costs resulting from the alteration of any operating variables. Results can be viewed in financial statement, tabular, or graphical form. The program was developed using Microsoft Visual Basic 3.0 for Windows and runs on an IBM or compatible computer under the Windows 3.1 environment.