裝配圖動(dòng)力輸出總成的設(shè)計(jì)（720轉(zhuǎn)-分）（有cad圖+文獻(xiàn)翻譯）

裝配圖動(dòng)力輸出總成的設(shè)計(jì)（720轉(zhuǎn)-分）（有cad圖+文獻(xiàn)翻譯）,裝配,動(dòng)力,輸出,總成,設(shè)計(jì),cad,文獻(xiàn),翻譯 車(chē)輛與動(dòng)力工程學(xué)院畢業(yè)設(shè)計(jì)說(shuō)明書(shū) Power takeoff shaft The power takeoff shaft usually called simply the power takeoff ,provides a means to drive the machine that are being towed by the tractor .the engine power of the tractor is being used not only to pull or carry the machine ,but also to operate it .typical exampled of machines that are power driven are mowers .,balers ,combine.potato harvests ,and manure spreader .the PTO provides a very useful source of power .and the alternative would be to fit an engine to each of these machine .this is ,of course done where the power required to drive the machine may be greater than the tractor can be supply. Generally most machines can be powered by the tractor . Power take off shaft are calssifily according to their location of the tractor,type of the drive .rotation speed ,and method of control . Most tractor are equipped with a rear PTO.some of them have a front PTO ,ROW-tractor use both a rear and a side PTO . AS to the type of drive, power take off shaft are classed as transmission drive .live ,semi-independent ,and ground-speed type ,the transmission drive PTO IS driven from the tractor transmission and so it will stop rotating whenever the engine clutch is disengage . The live PTO is driven from the engine crankshaft through the clutch driving member irrespective of the position of the clutch .the semi-independent PTO WILL continue to operate while the driver is shifting gears , but is incapable of being engaged or disengaged while the tractor is moving .the ground-speed PTO has its speed proportional to the ground speed of the tractor .such A PTO finds application on row-crop tractors to operate machine .such as mounted drills .whose working rate must be in synchronism with the ground speed of the tractor . The power takeoff are standardized at 540 and 1000rpm (AT nominal engine speed )the spined ends of PTO shaft of all tractor are of one and same size and are arranged at one and the same level relative to the tractor support surface .when the PTO Shaft is not used ,its end is covered by a guard stamped from sheet steel. Power takeoff shaft may be control by either mechanical or hydraulic means Live PTO shaft can be engage or disengage on the run by hydraulic or complex mechanical means. When the PTO is disengage , sun gear brake is released and planet carrier is applied. In this case ,PTO shaft is held stationary and the planet gear transmit rotation from the internal gear to the sun gear . When the PTO is engaged. sun gear brake is applied and planet carrier is released. The planet gears now have to walk around the sun gear .as the planet gears roll around the sun gear.they carry the planet carrier around with them .thus driving the PTO shaft which is rigidly connected the planer carrier. When the PTO is not used the PTO control lever is placed into its neutral (central) position. In this case.both the sun gear and the planet carrier brakes are released. Toothed clutch 1 inserted into the PTO driving line makes it possible to have either independent or ground-speed power takeoff. The clutch is operated by a control lever and can be placed into three different positions. When the clutch is shifted all the way forward (to the left .as shown in Fig.165a), drive shaft 9(see Fig.164) of the PTO nit is connected to the transmission main(output) shaft to obtain ground-speed power takeoff. If the clutch is moved all the way backward (to the right .as shown in Fig.165b). the drive shaft of the PTO unit will be connected to the engine crankshaft, and so power takeoff will be independent. With the clutch in its neutral (central) position . no drive is transmitted to the PTO unit. To place the clutch into the “GROUND-SPEED PTO”position, one should disengage the engine clutch, whereas placing it into the “LIVE PTO”position required that the engine should be stopped. THE HYDRAULICALLY CONTROLLED PTO UNIT (Fig.166) includes a planetary gear set and a self-contained hydraulic system. The unit is contained in a case that is attached to the rear axle housing of the tractor. The reduction gear set of the PTO unit comprises drive gear 3 carried on shaft 1 and driven gear 9 and hydraulic clutch 10 that are mounted on PTO shaft 5. The shafts are supported by ball bearings housed in bores in the PTO case. Drive gear shaft 1 is driven from the engine crankshaft, and so the unit provides splined to its shaft and is in constant mesh with a hub that is freely supported by ball bearings on the PTO shaft. The connection between the driven gear and the PTO shaft is effected by hydraulic clutch 10 similar to those described in Section 11.4. The clutch comprises a series of driving and driven discs accommodated in a drum that is splined to the PTO shaft. The clutch driving discs are made of steel and equipped with cermet linings. These discs are splined on to the drive gear hub. The clutch driven discs of plain steel are arranged alternately between the driving discs and are splined into the clutch drum. Inside the clutch drum, there is annular space 12 that plays the part of a hydraulic cylinder, into which fits piston 11. The piston is sealed in the annular space of the clutch drum by a cast-iron ring on the outside and a rubber ring on the inside and is loaded by a series of springs 14. To engage the clutch and hence the PTO shaft, oil is delivered under pressure into the annular space in the clutch drum. This causes the piston to move against spring pressure and tightly compress the pack of the clutch discs , thus connecting the PTO shaft to the driven gear of the reduction gear set. To disengage the clutch ,the annular space in its drum is connected to a return line leading to oil sump 7. Now, release springs 14 force the piston to expel the oil contained in the annular space and release the clutch discs. The piston carries a series of pins which ,at the end of the return stroke of the piston ,bring pressure to bear against the discs of brake 13 thus stropping the PTO shaft. Oil is let in and out of the clutch through passages drilled in the shaft. The hydraulic system of the PTO unit includes oil pump 4, oil intake filter 8, a valve arrangement ,and oil lines. The valve arrangement includes pressure regulator valve 15 and PTO control valve 4 (Fig.167) that are carried in a common housing bolted to the front wall of the PTO case. The pressure regulator valve maintains a constant pressure (1 Mpa) irrespective of the delivery of the oil pump. The PTO control valve is essentially a ball valve loaded by two springs and operated by a plunger and an eccentric held to the shaft of PTO control lever8. When the PTO shaft is engaged ,the control valve also doubles as a relief valve. With PTO control lever in the “OFF”position (Fig.167a). the eccentric on the control lever shaft releases the control valve plunger, which relieves the ball valve of spring pressure. In this case ,oil pump 5 draws oil from the oil sump of the PTO case through oil intake filter 1 and delivers via the discharge line to both valves of the valve arrangement . Since PTO control valve 4 is relieved of spring pressure ,the oil flows past it and return to the sump, some oil going through passage 3 drilled in the PTO shaft to lubricate the friction discs of hydraulic cultch 2. When the PTO control lever is placed into the “ON” position (Fig.167b),the eccentric turns and depress the control valve plunger. As the plunger is depressed , it compresses both control valve springs which,in turn, push the valve against its seat. This closes the oil return passage to the sump. Since there is no escape route open to the oil ,the pressure in the system goes up ,and the oil is forced into annular space 6 of the clutch and causes the cultch piston to the PTO shaft. The oil pressure will rise to 1 Mpa ,at which point pressure regulator valve 7 will come into operation to maintain this pressure invariable. To make the clutch engage smoothly ,the PTO control lever should be operated slowly. designated person responsible for safety. Therefore, the owner was not in compliance with Title 8 Program. (As of July 1, 1991 the State of California requires all employers to have a written seven point injury prevention program: designated safety person responsible for implementing the program; m California Code of Regulations 3203 -- Injury and Illness Prevention ode for ensuring employee compliance;hazard communication; hazard evaluation through periodic inspections; injury investigation procedures; intervention process for correcting hazards; and a health and safety program.) INCIDENT On December 22, 1991 at approximately 8:00 a.m. a 30 year old male Portuguese farm laborer was driving a farm tractor which was pulling a dairy feed wagon. The power take off unit at the rear of the tractor was driving the feed dispensing auger system inside the feed wagon. (A power take off unit (P.T.O.) is an extension of the tractor transmission shaft used to power implements with the tractor engine.) This is a common method of feeding the dairy cows by using the auger to mix the feed and push the cattle feed out. The P.T.O. was apparently not functioning correctly, and the employee left the tractor engine idling and climbed off the tractor to check the attachment. The employee was standing next to the P.T.O. when he turned to reach up and pull the hydraulic lever on the rear of the tractor which engages or disengages the P.T.O. At this time his left shirt sleeve was caught on the rotating shaft of the P.T.O. The employee was wound around the P.T.O shaft as it rotated. The rotation of the shaft wedged him into the metal frame around the P.T.O. shaft and sheared his arm almost completely off. He also hit his head on the metal frame, receiving a 2 centimeter laceration on his scalp near the back of his head, and a cervical fracture. The tractor engine stalled at this time because it was idling at low speed and jammed by the body of the farm laborer. He lost consciousness for an unknown length of time; when he regained consciousness he called for help and was found by co- workers. Employees at the dairy called the local ambulance service and then disconnected the P.T.O shaft in order to extricate the injured worker's arm. At this time his left arm almost completely detached about half way between his shoulder and elbow, remaining connected only by skin and muscle. The ambulance crew immobilized his spine, splinted his arm, gave oxygen, started an I.V. and transported him to the emergency department of the local hospital. He was stabilized and transferred four hours later by helicopter to a microsurgery medical center 200 miles from the incident to have his arm reattached. Because of the extensive damage and loss of tissue to his arm, reattachment was not attempted and the arm was surgically amputated approximately six inches below his shoulder. Currently, the employee is in rehabilitation and is planning to return to work at the dairy. PREVENTION STRATEGIES 1. The shaft and universal joints of the P.T.O. should be guarded by commercially available shields which cover moving parts. This P.T.O. was not shielded at the time of the incident, which is a violation of California law* and recognized safety practice, in this case leading directly to the amputation of the worker's arm. At the time of our investigation, the dairy owner had purchased and installed guards on the P.T.O. of the involved tractor. If the P.T.O. shaft had been guarded at the time of the incident, the worker's sleeve would have not been caught and he would not have lost his arm. * California Code of Regulations T8 3440 (subparagraph c) requires that all P.T.O. units and drivelines be guarded. 2. All equipment should be checked prior to beginning daily work activities. This allows the worker to make sure that all equipment is working correctly, before any work is initiated. A regular check of the tractor and feed wagon prior to its use would have identified the problem of the malfunctioning P.T.O. The worker could then have had this fixed before trying to use it. 3. The design of the tractor permitted the driver to reach behind while still in the seat to pull the lever for the P.T.O. Therefore, he should not have tried to reach the lever from the ground. Because he was standing near to the rotating shaft while he was attempting to adjust the P.T.O. he came into contact with the rotating shaft. If he had remained in the seat this would not have occurred. 4. Workers should disconnect the power source and wait for all machine movement to stop before servicing equipment.* If the employee needed to leave the tractor, he should have turned the tractor engine off prior to leaving the tractor seat. He would not have come into contact with the rotating P.T.O. shaft if he had complied with this regulation. Note: * (California Code of Regulations T8 3441 Paragraph a (subsection c) requires that power sources be disconnected and machine movement stopped before servicing equipment) 5. This worker had only been working at this dairy for 3 months although he had worked at different dairies for approximately 10 years. Since he had begun working at this dairy, he had received no safety training related to equipment or job tasks or hazard identification*. If he was trained on how to recognize and avoid hazards he might not have lost his arm. Note: * California Code of Regulations T8 3383 (subparagraph b) requires workers to receive safe operating and servicing instructions at the time of their initial assignment. 6. This incident occurred because loose clothing worn by the worker was caught in the rotating P.T.O. shaft. If the worker had better fitting clothing this incident would not have occurred*. The owner of the dairy was wearing a loose shirt at the time of this investigation, which indicates that he still did not recognize this as a hazard. This is an inexpensive and relatively simple way of preventing machinery entanglement. Note: * California Code of Regulations T8 3383 (subparagraph b) requires that loose clothing that could be entangled in machinery should not be worn. 動(dòng)力輸出軸 動(dòng)力輸出通常被簡(jiǎn)稱(chēng)為PTO軸。它提供一種途徑去驅(qū)動(dòng)農(nóng)機(jī)具工作。牽引力不僅僅用來(lái)牽引農(nóng)機(jī)具，而且用來(lái)操縱控制它。典型的機(jī)械例子就是割草機(jī)，打包機(jī)，聯(lián)合收割機(jī)和施肥散布機(jī)。動(dòng)力輸出軸提供了一個(gè)非常有用的能量源，根據(jù)農(nóng)機(jī)具的不同選用不同的軸頭。動(dòng)力輸出所提供的動(dòng)力可能 比直接從拖拉機(jī)引出的動(dòng)力要強(qiáng)勁。動(dòng)力輸出總成的分類(lèi)，根據(jù)PTO軸在拖拉機(jī)上位置的不同，驅(qū)動(dòng)方式和控制方式的不同進(jìn)行分類(lèi)的。根據(jù)驅(qū)動(dòng)方式的不同拖拉機(jī)動(dòng)力輸出分成非獨(dú)立式的，獨(dú)立式的，半獨(dú)立式的和同步式的。非獨(dú)立式的它的動(dòng)力直接從變速箱傳遞過(guò)來(lái)的，在離合器分離的時(shí)候，PTO軸就會(huì)停止工作。獨(dú)立式PTO軸就是它的動(dòng)力直接來(lái)源于發(fā)動(dòng)機(jī)曲軸，它的工作情況和離合器的工作沒(méi)有聯(lián)系。半獨(dú)立式PTO軸，在齒輪換檔時(shí)候，仍然能工作，但是在拖拉機(jī)運(yùn)動(dòng)時(shí)，它是沒(méi)有辦法進(jìn)行嚙合和分離的。同步式PTO軸，它的速度和輪子的轉(zhuǎn)速成比例。最好的例子就是播種機(jī)，它的工作速度必須和拖拉機(jī)的移動(dòng)成比例 PTO軸的軸頭按標(biāo)準(zhǔn)分為1000r/min和540r/min兩種類(lèi)型。所有的拖拉機(jī)盡量做成這兩種標(biāo)準(zhǔn)，這樣有利于維修和替換。當(dāng)動(dòng)力輸出軸不工作時(shí)候，它通常用鐵制的軸頭保護(hù)罩，保護(hù)軸頭免受傷害。 PTO的分離和嚙合可以通過(guò)機(jī)械力或者液壓的方式控制。PTO箱體一般被安裝在PTO總成箱體里。一般是由主動(dòng)齒輪，從動(dòng)齒輪組成的，從動(dòng)齒輪可以在低速軸的中間滑動(dòng)，和主動(dòng)齒輪嚙合。這種嚙合必須在拖拉機(jī)停車(chē)的情況下進(jìn)行。 獨(dú)立式的PTO可以通過(guò)液壓和復(fù)雜的機(jī)械控制其工作，PTO總成包括中心輪，太陽(yáng)輪和行星輪，行星輪被放置在行星架上。還有兩種鼓式剎車(chē)片，一種是作用在行星齒輪上的，另一種是作用在太陽(yáng)輪上的，太陽(yáng)齒輪的輪轂被牢牢的固定在剎車(chē)片上，剎車(chē)片通過(guò)球軸承被安裝在PTO軸上，剎車(chē)片被固定在軸上。鋼制的剎車(chē)片上裝有摩擦襯套，剎車(chē)片一端用銷(xiāo)釘固定，另一端和曲軸，調(diào)整螺栓連接。通過(guò)其對(duì)動(dòng)力輸出進(jìn)行控制。 在PTO軸沒(méi)有嚙合的情況下，中心輪的剎車(chē)片被釋放，行星輪的剎車(chē)片工作。這樣的話PTO軸不旋轉(zhuǎn)，中心輪和太陽(yáng)輪之間的旋轉(zhuǎn)通過(guò)行星輪的旋轉(zhuǎn)而進(jìn)行的。當(dāng)PTO軸嚙合時(shí)，控制太陽(yáng)輪的剎車(chē)片工作，而行星輪的剎車(chē)片被釋放，行星齒輪現(xiàn)在不得不繞著太陽(yáng)輪旋轉(zhuǎn)，當(dāng)行星齒輪繞著太陽(yáng)輪旋轉(zhuǎn)的同時(shí) ，行星齒輪架也跟著旋轉(zhuǎn)，因?yàn)樾行驱X輪架和PTO軸是固結(jié)的，所以行星架帶動(dòng)PTO軸一起旋轉(zhuǎn)。當(dāng)PTO軸不工作的時(shí)候，PTO軸不使用的時(shí)候。PTO控制桿必須放在中間位置，太陽(yáng)齒輪和行星齒輪的剎車(chē)片被同時(shí)釋放。 牙式離合器被裝入PTO的傳動(dòng)鏈中，這樣使得它有可能成為獨(dú)立式和同步式的兼容體。離合器通過(guò)控制杠桿工作，杠桿有三個(gè)位置，離合器換檔向前，PTO軸被連接到變速器的輸出軸，這樣就獲得了與輪速成比例的轉(zhuǎn)速。如果離合器的控制桿件向后運(yùn)動(dòng)，PTO軸就和發(fā)動(dòng)機(jī)曲軸直接相連，因此發(fā)動(dòng)機(jī)就獲得了獨(dú)立輸出。如果在中間位置，沒(méi)有動(dòng)力傳輸?shù)絇TO總成上。當(dāng)離合器放置在同步檔位上時(shí)，我們應(yīng)該先斷開(kāi)離合器，若要進(jìn)入“獨(dú)立式”的工作模式，也要求發(fā)動(dòng)機(jī)停機(jī)。 液壓控制的PTO總成的齒輪機(jī)構(gòu)包括在軸上的主動(dòng)齒輪和被動(dòng)齒輪，液壓離合器。液壓離合器被安裝在PTO軸上，PTO軸通過(guò)球軸承安裝在箱體上，一軸的動(dòng)力是直接由發(fā)動(dòng)機(jī)曲軸傳遞過(guò)來(lái)的，因此這種PTO軸總成提供了一種獨(dú)立的動(dòng)力輸出。主動(dòng)齒輪和從動(dòng)齒輪屬于常嚙合類(lèi)型，從動(dòng)齒輪固定在輪轂上，輪轂通過(guò)球軸承安裝在PTO軸上。從動(dòng)齒輪和PTO軸的連接是通過(guò)液力離合器連接的，液力離合器有一系列主動(dòng)盤(pán)和從動(dòng)盤(pán)構(gòu)成，從動(dòng)盤(pán)被鉚接到到齒輪輪轂上，離合器的主動(dòng)盤(pán)是由鋼鐵制成的，內(nèi)部安裝有耐磨襯套，這些主動(dòng)盤(pán)被安裝在主動(dòng)齒輪輪轂上，離合器的從動(dòng)盤(pán)也是有鋼鐵壓鑄而成的。 為了使離合器工作PTO軸工作，液壓油在壓力的作用下，被壓入離合器空腔，這就使得活塞移動(dòng)，頂開(kāi)預(yù)緊彈簧，繼而壓緊離合器盤(pán)片，連接PTO軸和從動(dòng)盤(pán)總成。 在PTO軸不工作的時(shí)候，環(huán)狀空腔和回油管相連，回油管道把油流到到外部油箱,這種情況下，回位彈簧把環(huán)狀空腔里的油排出來(lái)。釋放盤(pán)片，在活塞回程的最后一段，活塞帶走了一系列用于產(chǎn)生盤(pán)片壓力的銷(xiāo)子，最終PTO軸停止轉(zhuǎn)動(dòng)，油通過(guò)軸上的油道流出離合器。 液力PTO總成包括液壓泵，進(jìn)油濾清器，多種閥門(mén)和油路。其中閥門(mén)包括調(diào)壓閥和PTO控制閥門(mén)。PTO控制閥被放置在一個(gè)箱體上。這個(gè)箱體被螺栓固定在PTO箱體的前部。無(wú)論油泵輸出的油壓大小，調(diào)壓閥使得輸出的液壓油保持一個(gè)恒定的油壓。PTO控制閥本質(zhì)上受彈簧力作用的球閥控制，通過(guò)PTO控制桿件上的偏心機(jī)構(gòu)調(diào)節(jié)。當(dāng) PTO軸工作時(shí)，控制閥還可以當(dāng)作減壓閥來(lái)使用。 當(dāng)PTO控制桿件在“OFF”位置上時(shí)，控制機(jī)構(gòu)上的偏心器釋放控制閥的活塞，這個(gè)活塞本用來(lái)減小球閥的彈簧力的。在這種情況下，油泵把油從油箱中抽取出來(lái)，油通過(guò)濾清器、油管到多路閥中，因?yàn)榭刂崎y較小了彈簧力，所以液壓油流過(guò)控制閥經(jīng)過(guò)軸上的油道又流回到油箱里。而一些液壓油經(jīng)過(guò)軸上的油道潤(rùn)滑部件。 當(dāng)PTO控制桿件在“ON”的位置時(shí)，偏心器壓下控制柱塞，當(dāng)柱塞被壓下，他們共同壓縮彈簧，同時(shí)使閥體頂壓閥座，這樣就切斷了回油的線路，此時(shí)，管路中的壓力升高，液壓油進(jìn)入離合器，壓緊盤(pán)片，使從動(dòng)盤(pán)和PTO軸一起轉(zhuǎn)動(dòng)，當(dāng)油壓上升到1Mpa時(shí)，油壓保持不變，使得液力離合器順利工作。 A farm laborer was feeding the cows on a dairy farm.一名農(nóng)場(chǎng)工人在奶牛場(chǎng)飼養(yǎng)奶牛，He drove a tractor which pulled a feed wagon.他駕駛一輛拖拉機(jī),拉著一車(chē)飼料. Inside the wagon a large metal screw (or auger) turned, mixing the feed and pushing it out.在拖拉機(jī)后部旋轉(zhuǎn)的軸頭用來(lái)混合飼料, This screw in the wagon was connected by a driveshaft to the power-take-off unit at the back of the tractor.軸頭連接了拖拉機(jī)和牽引件，并且在高速旋轉(zhuǎn)，沒(méi)有保護(hù)罩加以保護(hù). The worker got off his tractor to check the driveshaft, leaving the tractor idling and the shaft still turning.工人下了拖拉機(jī)，檢查動(dòng)力輸出軸,此時(shí)，拖拉機(jī)空轉(zhuǎn)及軸仍然轉(zhuǎn)動(dòng). When he reached across the shaft to pull a lever on the tractor, his shirt sleeve was caught by a joint in the shaft.當(dāng)他拉過(guò)了軸拉杠桿時(shí)候，拖拉機(jī)軸頭卷住了他的襯衫袖子. 軸The worker was wrapped around the shaft, his arm was ripped almost completely off, and his neck was fractured.裹住手臂,手臂被撕開(kāi),幾乎完全被卷進(jìn)去,他的脖子被打斷. The worker survived, but lost his arm.工人存活,但失去了他的手臂. How could this injury have been prevented?這怎么可能傷得到預(yù)防? All power take off units and shafts must have guards, shields, and sleeves.一切的動(dòng)力輸出都要加裝安全保護(hù)罩. · Check equipment before using it.檢查設(shè)備,然后用它. · Turn the power off and wait for the machine to stop moving before fixing it.關(guān)閉電源,等待機(jī)器停止，再操縱。 · Give workers safety training.為工人提供安全訓(xùn)練. · 在操縱機(jī)器時(shí)，Do not wear loose fitting clothing around machinery.不要穿著寬松的衣服. BACKGROUND背景 In December, 1991 a California Occupational Safety and Health Administration (Cal/OSHA) district compliance office reported to the NURSE project that a dairy farm employee's left a rm had been amputated in a work-related injury.121991加州職業(yè)安全與健康管理局(cal/osha)民政廳公布了保護(hù)項(xiàng)目,一個(gè)奶牛場(chǎng)員工留下了PTO軸被截去了手臂. The incident occurred while the dairy farm laborer was driving a tractor pulling a cattle feed wagon.事件發(fā)生時(shí),奶牛場(chǎng)的工人正開(kāi)著拖拉機(jī)的牛飼料車(chē)皮. Four days after the incident the dairy owner notified Cal/OSHA, who conducted an investigation within a few days.事件發(fā)生四天后牧場(chǎng)主人通知世界衛(wèi)生組織，此時(shí)，世界衛(wèi)生組織進(jìn)行了一次調(diào)查,在短短數(shù)天. A nurse from the NURSE project interviewed the injured worker in the hospital on January 22, 1992, and a Senior Safety Engineer, epidemiologist, and nurse from the NURSE project conducted an on-site investigation on February 13, 1992.一位護(hù)士在醫(yī)院采訪受傷工人。在1992年1月22日,一名高級(jí)安全工程師,epidemiologist,護(hù)士進(jìn)行了現(xiàn)場(chǎng)調(diào)查,2月13日1992. The NURSE staff discussed the incident with the owner of the dairy and took photographs of the feed wagon and other equipment with the employer's consent.護(hù)理人員和牧場(chǎng)主討論這一事件在雇主的同意下拍照。 The incident occurred on a dairy that has approximately 500 cows and 20-25 calves.這一事件發(fā)生的牧場(chǎng),擁有大約500頭牛和20-25小牛. The staff consists of two members of the family that owns the dairy, five full-time employees, and two summertime employees.有關(guān)人員分為兩個(gè)家族成員擁有這個(gè)牧場(chǎng),5名全職員工,以及兩位臨時(shí)工. This is a relatively small dairy in which the farm laborers performed a variety of tasks, including tractor driving.這是一個(gè)相對(duì)小型牧場(chǎng)，農(nóng)民工進(jìn)行了各種任務(wù),其中包括拖拉機(jī)駕駛. At the time of the incident the dairy had no written injury prevention program, no safety training, and no designated person responsible for safety.在當(dāng)時(shí)的事件, 牧場(chǎng)沒(méi)有書(shū)面的傷害預(yù)防計(jì)劃,沒(méi)有安全培訓(xùn),并沒(méi)有指定負(fù)責(zé)人的安全. Therefore, the owner was not in compliance with Title 8 California Code of Regulations 3203 -- Injury and Illness Prevention Program.因此,這里的主人是不符合職稱(chēng)8州法規(guī)3203--傷害和疾病防治法規(guī). (As of July 1, 1991 the State of California requires all employers to have a written seven point injury prevention program: designated safety person responsible for implementing the program; mode for ensuring employee compliance;hazard communication; hazard evaluation through periodic inspections; injury investigation procedures; intervention process for correcting hazards; and a health a