Modified Screw Jack for Lifting Operation in Industrial Setting Benjamin Ezurike 1a*, Modestus Okwu 2b

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1 International Journal of Enineerin and Technoloies Submitted: ISS: 97-63X, Vol. 13, pp Revised: doi: / Accepted: SciPress Ltd., Switzerland Online: Modified Screw Jack for Liftin Operation in Industrial Settin Benjamin Ezurike 1a*, Modestus Okwu b 1 Department of Mechanical Enineerin, Madonna University, ieria Department of Mechanical Enineerin, ederal University of Petroleum Resources Effurun, ieria. a* ben4oke000@yahoo.com; b mechanicalmodestus@yahoo.com Keywords: Scissor jack; ear arranements; quick liftin; ear mechanism Abstract. With the increasin level of technoloy, researchers all over the world are workin continuously to improve and implement better and robust desin of materials at workplace for productivity, efficiency and effectiveness. Detailed desin procedure of a quick liftin screw jack is presented in this paper. The desin is fundamentally a modification of the conventional scissor jack. The problems associated with the conventional jacks are the eronomic snas experienced by operators due to proloned bendin or squattin positions durin operation. These problems of waist pain and backaches are as a result of continuous turnin of the wrench or crank shaft in an uncomfortable position for a lon period. These led to the desin and modification of quick liftin screw jack with ear arranements that are safe, reliable and capable of raisin or lowerin heavy load with little effort. The results showed that the introduction of the crank and ear mechanism would help reduce difficulty in operation, reduce time, increase efficiency and effectively control the difficulties concomitant with Eronomics - which is an ultimate sensitivity in desin process. 1. Introduction Over the years, enineers, scientist and eronomist have extolled the conventional automobile screw jack (scissors jack) as bein very efficient, yet continue to seek new desins to increase reliability and reduce its shortcomins and maintenance costs. Screw application is used in the elevation of vehicles or objects. The operation of the screw jack is such that it comprises a handle for drivin a bolt element (Lead Screw) manually to adjust the heiht of the jack to elevate a vehicle or an object. Existin jacks are of reat disadvantae to elderly women especially under unfavorable weather condition [1]. A mechanical jack is a device which lifts weihty or heavy equipment and vehicles so that maintenance can be carried out underneath at workplace or manufacturin settin []. A jack screw is a type of jack which functions by turnin a lead screw. It is commonly used to lift heavy load to a heiht. A ood example is the car-jacks. In the case of a screw jack, a small force applied in the horizontal plane is used to raise or lower lare load [3]. A ood number of operational staff in manufacturin, bottlin, oil and as and other multi-national companies perform task in a squattin or cowerin position for a lon period. These results to inefficiency at workplace due to eronomically imbalance position they encounter which often times ive rise to back ache and poor body architecture in the future. These present available jacks further require the operator to remain in proloned bent or squattin position to operate the jack. Due to its difficulties, body pains, back ache and others can emere as a result of continuous turnin of the wrench or crank shaft in an uncomfortable position for a lon period. The statement of problem has led to the motivation of desinin a modified quick liftin screw jack with ear arranement. The introduction of the bevel ear will help reduce difficulty in operation with a handle incorporated in the desin and also reduce time spent to a very minimum Screw Jack and Types Automobile screw jacks or jack screw is a device that is used to lift an automobile in order to carry out repairs or maintenance. Screw jacks are desined with materials havin the capabilities and properties to lift heavy loads and prevent bucklin, wear etc. which can result to unforeseen SciPress applies the CC-BY 4.0 license to works we publish:

2 40 Volume 13 accidents. Screw jacks have been used for more than 50 decades with new developments and redesins [3]. The conventional screw jack (which is the scissors jack) is still commonly used due to its many advantaes such as lon life span, strenth, packain, mobility, cost etc., with the reatest to be its self-lockin attribute, which means when the rotational force on the screw is removed, it will remain motionless where it was left and will not rotate backwards, reardless of how much load it is supportin. This makes them inherently safer than hydraulic jacks, for example, which will move backwards under load if the force on the hydraulic actuator is accidentally released. Mechanical advantae is important in car jacks because it enable human lift a vehicle by manual force sinle-handedly. More powerful jacks use hydraulic power to provide more lift over reater distances. Mechanical jacks are usually rated for maximum liftin capacity. This is peculiar in developin nations where traditional screw jacks are often in use. [4, 5] desined and fabricated a motorized automated object liftin jack usin electric motor for liftin and lowerin of heavy loads. The electricity for the operatin the jack was from the direct current (dc) battery with increased mechanical advantae. Okoronkwo et al. [6] developed hand water pump usin quick return crank mechanism. Chaudhary et al. [7] desined a screw jack usin solid works 010, after the desin, they constructed the jack usin available machine tools like: lathe, rindin, threadin and millin machines. The developed jack was tested and found effective in addressin eronomics issues. Kumar et al. [8] desined and constructed screw jack by takin into consideration worm and spur ear arranement. The component part that makes up the developed system consist of the worm ear, spur ear, ball bearins and circular shafts. They considered soft enineerin materials in the development of the worm ear. The materials taken into consideration include alloys of metal like aluminum and bronze. In the desin of the liftin screw they considered a touh and heat treated hard material and also performed failure analysis in considerin the appropriate screw shaft. There are different kinds of jacks available; a ood example is the bumper jacks obtainable in older cars and scissor jacks, quite common in newer cars. The tension force applied by the jack lead screw ives rise to a compressive force. An Acme thread is a very touh and stron thread often used and is capable of resistin the lare loads imposed on most jack screws. Car jacks usually use mechanical advantae to enable vehicle liftin. There are two types of automotive car jacks: Hydraulic and Screw type. The screw type is common. The screw-type devices has a very reat advantae which has to do with the tapered sides of the screw wear, the matin nut automatically comes into closer meetin, instead of allowin backlash to develop [9]. There are also cateories of screw and hydraulic jacks. Hydraulic jacks have a bottle shape. By operatin the handle, which is a lever (a simple machine), fluid is compressed and routed to an actuatin cylinder which results in lift. Other examples of hydraulic type of screw are hydraulic jack, bottle jack, floor jack, friction jack, and racketin jack. Parker and Pickup [10] revealed the accurate and precise pronostication of a screw thread, the tedious nature and time taken to achieve the liftin process. Different desin of threads are shown conventionally on enineerin drawins. It is also very important to note the need to lubricate screw jacks with rease on reular basis. Another type of screw is the ball screw which is quite unconventional and uses recirculation-ball nut to minimize friction and prolon the life of the screw threads. The major disadvantae of this kind of ball screw is its inability to selflock [11]. Attention of researchers has been drawn to the failure of screw in manufacturin and production companies. The major causes of screw failure is attributed to poor desin, lack of rease and poor enineerin practices [1].

International Journal of Enineerin and Technoloies Vol. 13 41 iure 1. Detailed view of ear drive arranement in proposed desin. 1.. Principle of Operation iure. Gear drive arranement in proposed desin.

3 International Journal of Enineerin and Technoloies Vol iure 1. Detailed view of ear drive arranement in proposed desin. 1.. Principle of Operation iure. Gear drive arranement in proposed desin. Durin usae, the screw jack is assembled for operation with i. 7 extended properly. The jack is then placed perfectly under the vehicle with i. loadin platform servin as a base for support. i. 4, functions as the effort that aids rotation of i. 3. Durin the process of liftin i. 4 rotates in clockwise direction allowin i.3 rotate as well (enain earin motion) which aids in the upward movement of i.. The reverse is the case when i. 4 is turned counter clockwise, allowin downward movement of i. 3 thereby lowerin the load. Doin all these like the conventional screw jack (scissors jack), the operator must carefully inspect the operation makin sure the load sits perfectly on the loadin platform to prevent unsafe conditions i.e. slippae of the vehicle from the jack.

4 4 Volume 13 iure 3a. Crank disc and crank disc pinion. PISTO ROD 1 1 A B L C G H E I K C L B A D J J D K I jack TABLE G E H handle iure 3b. Quick-return crank mechanism showin crank disc pinion positions alon its path profile and relative to crank beam positions and piston rod attachment point path profile. [6]. Desin Analysis and Calculation Material Selection of Parts: The choice of material is very important in the desin of an automobile jack as in the case of other enineerin desins. It is one of the most important decisions a desiner is called to make. The decision is usually made before the dimensions of the part are established. One very important factor in material selection is the strenth. Other factors include wear, corrosion, weiht, noise, lubrication, marketability, manufacturability, safety, functionality, cost, etc. Some aforementioned have to do unswervinly with the dimensions, the material, the processin, and the joinin of the element of the system. or effective performance of jack, mild steel is majorly used because of its strenth, touhness and low cost. It provides material properties that are acceptable for the application. inally, the selected material of mild steel ives a reduced weiht of the jack.

development of three-dimensional (3-d) desin from which conventional

allows rapid and accurate modelin, calculation of mass properties, location

5 International Journal of Enineerin and Technoloies Vol Computational Tools: Computer-aided desin (CAD) software allows the development of three-dimensional (3-d) desin from which conventional two-dimensional (-d) orthoraphic views with automatic measurement can be produced. The CAD software packae used for this project is Solid works 015, which allows rapid and accurate modelin, calculation of mass properties, location of center of ravity, -d and 3-d views etc., with lots of material selections for parts or member. iure 4. Power screw. iure 5. Bevel ear. iure 6. Crank Handle. iure 7. Bearins.

44 Volume 13 iure 8. Jack frame. iure 9. Stand. iure 10. Bracket..1. General Desin Calculations.1.1. Determination of a Velocity Ratio iure 11.

Velocity ratio of ears can be calculated usin Equation 1 as iven by [13]: t VR, (1) n T where, = umber of revolutions of driver ear, n = umber of

. Determination of Gear Parameters where Allowable tooth stress can be calculated by Equation 3.

3, () V Bendin stress or permissible workin stress (Ϭ) in the tooth can be calculated by Equation 3.

6 44 Volume 13 iure 8. Jack frame. iure 9. Stand. iure 10. Bracket..1. General Desin Calculations.1.1. Determination of a Velocity Ratio iure 11. Bolt and ut. Velocity ratio of ears can be calculated usin Equation 1 as iven by [13]: t VR, (1) n T where, = umber of revolutions of driver ear, n = umber of revolutions of driven ear, T = umber of teeth of driver ear, t = umber of teeth of driven ear.1.. Determination of Gear Parameters where Allowable tooth stress can be calculated by Equation 3.5, iven by [14]: S o S S a o 3 Endurance strenth, V= Pitch line velocity, and V<10m/s. 3, () V Bendin stress or permissible workin stress (Ϭ) in the tooth can be calculated by Equation 3. Ϭ = ( W * h)*6 T, (3) b* t where W T = Tanential load actin on the tooth, h = Lenth of the tooth, b = Width of ear face, t = Tooth thickness. Dynamic tooth load can be calculated usin Equation 4 also iven by [15]; d 1V ( bc ) 1 V bc, (4) where V = Pitch line velocity, b = ace width, C = Constant which depends on the tooth form, material and deree of accuracy with which the tooth is cut, = orce or Tanential load actin on the tooth. orce above can be calculated by usin Equation 5 M t, (5) D

7 International Journal of Enineerin and Technoloies Vol where M t = Gear torque, D = Pitch diameter of ear. Wear tooth load is iven by Equation 6 D bkq w p (6) where D p = Pitch of smaller ear (pinion), b = ace width of ear, K = Stress factor of fatiue, Q = Gear factor. Gear factor in Equation 6 can also be calculated, usin the Equation 7 Q p, (7) where = umber of teeth on ear, p = umber of teeth on pinion. In desin of conventional conventional liftin jacks, the total force required to lift the piston durin the upward stroke is equal to the sum of the followin [13] L P r, (8) where p = orce due to the weiht of the piston, r = orce due to the weiht of the piston rod, w = orce due to the weiht of the vehicle havin a cross-section equal to that of the jack. Piston weiht and the piston rod weiht are due to the inertia force. Therefore, the stepwise evaluation of these forces is presented. Since the piston weiht and piston rod weiht possess mass, the inertia force actin on them must be evaluated. Generally, inertia force is a product of mass and acceleration.therefore, the inertia force due to the piston is obtained by multiplyin the mass of the piston by the acceleration. Thus, the inertia force of the piston is iven as: M W a piston W inertia. (9) But the acceleration of the piston can be evaluated usin the expression ivin by [14] a p.max S, (10) where S = Piston stroke, = Anular velocity of the drivin the drivin crank. Power required to drive the ear train can be calculated usin [13]: T t H S W, (11) L 60 D where, η = Gear drive efficiency. In conventional liftin jack desins, the ratio W: i P is usually lare so that i P can be assumed neliible. Also, the force due to weiht of piston rod is usually small compared to that, due to the weiht of the vehicle. W ma a d c W H, (1) W st 4 where = The mechanical advantae, W a = Allowable maximum load for users, R = Power input throuh the crank handle, R = Crank radius Determination for Desin of Power Screw In desinin an acme thread power screw for jack operation, the screw must be self-lockin and have strenth to prevent bucklin and safe enouh to prevent harm. The coefficient of friction in screw thread is independent of axial load, practically independent of speed, decreases with heavier lubricants, show little variation with combination of materials. The screw also should have a safe bearin pressure (Pb) on threads to protect the movin surfaces from abnormal wear. or safe

8 46 Volume 13 bearin pressure, Pb = MPa. Coefficient of friction = for steel because the material is known under reasonably constant service conditions subjected to loads and stresses that can be determined easily. [13]. To check for safety of lead screw, compressive stress induced in the screw due to load is iven as follow: Therefore, factor of safety = or the screw to be safe in tension, c W. (13) d c 4 yieldstress c t. (14) p*4 d, (15) c * where P = Pitch, d c =core diameter of screw, d m =mean diameter, c =compressive stress, W= load, Y= yield stress obtained from the material properties of the screw, = tensile stress. Outside diameter of screw, Mean diameter of screw, Helix anle of screw ( ), Anle of friction, d o = d c + P. (16) 1 ( ) d ( ) d m c d. (17) o tan 1 p ( ). (18) d m where μ= co-efficient of friction, assumed Hence for self-lockin to be possible,. Torque required to raise the load can be calculated as tan 1, (19) d m W T tan( ). (0) The pitch of bevel ears is measured at the lare end of the tooth. It should be noted that the clearance is uniform. [14, 15] The pitch anles are defined by the pitch cones meetin at the apex as shown in i. 9. The pitch anles are related to the tooth numbers as follows and p tan (1) p tan, () p

9 International Journal of Enineerin and Technoloies Vol where = Pinion pitch anles, = Gear pitch anles, = Pinion tooth number, = Gear tooth number. Gear ratio, therefore m c. (3) The input speed ( 1 ) to the ear drive from the handle was obtained usin the relation: p (4) where T = Output torque (m), T 1 = Input torque (m), 1 = Input speed (rpm), = Output speed (rpm), G.R. = Gear Ratio. The output speed ( ) in equation 4 was obtained usin the relation: where IM3 = Averae speed imposed by an operator on the jack handle. The output torque (T ) in equation 4 was also obtained usin the relation: (5) where r p = Radius of crank disc pinion circular path profile, M.A. = Mechanical advantae obtained from equation. The input torque (T 1 ) was dependent on one of the objectives of the study which required the reduction of the effort (enery) applied to lift an object by an operator by at least 50%. Accordin to R.S. Khumi [3], torque may be defined as the product of force and the perpendicular distance of its line of action from the iven point or axis. Hence, this force was obtained from the effort applied at the handle which drives the shaft which in turn drives the driver bevel ear. The effort on the handle was obtained usin the relation: (6) where E IM3 = Measured effort applied by an operator on the liftin jack handle. Thus, Input torque (T 1 ): Where d 1 = Perpendicular distance between effort line of action on handle and input shaft. (7) (8) 3. System Performance Let Torque (T) on shafts 1,, 3, 4, 5, 6, 7 and 8 represent T1, T, T3, T4, T5, T6, T7 and T8 respectively. Then, the ears in the ear drive equal: P, Q, R, S, M,, O, A, B, C, D, E, and as shown in i 3a. The rotary motion of the handle is transmitted to the driver ear P throuh the input shaft 1.Gear P meshes with ear M. Attached to ear M is ear Q which meshes with ear. Gear R meshes with ear O and ear S is attached to ear O. Gear S meshes with an idler ear A which in turn meshes with ear D. Gear D was attached to ear B which meshes with ear E. Gear C was attached to ear E and meshes with ear throuh the output shaft 8. The motion of ear 8 rotates the crank disc about the axis of the output shaft 8.

48 Volume 13 iure 1. Side view of the jack. iure 13. Exploded view of the jack. iure 14.

Gear Ratio relationship between ears in ear drive.

1:1 A;D 51;15 1:3.4 B;E 51;15 1:3.4 C; 51;15 1:3.4 3.1. Analysis of Previous Desin aainst

system hence 50% queue reduction at service stations. See Table

10 48 Volume 13 iure 1. Side view of the jack. iure 13. Exploded view of the jack. iure 14. Pictorial view of the jack when folded. Table 1. Gear Ratio relationship between ears in ear drive. Gear umber of Teeth Gear Ratio P;M 6;18 3:1 Q; 6;18 3:1 R;O 9;18 :1 S;A 10;51 5.1:1 A;D 51;15 1:3.4 B;E 51;15 1:3.4 C; 51;15 1: Analysis of Previous Desin aainst Modified Desin It requires far lesser time to lift an object compared to the lever powered system hence 50% queue reduction at service stations. See Table and 3. Table. Time Relationship between Lever Lift and Quick-return Crank Lift System. System Time (seconds) required to lift a car Capacity (k/m) Lever Lift System Quick-return crank Lift System

11 International Journal of Enineerin and Technoloies Vol Table 3. Effort and Torque Relationship between Lever Lift and Quick-return Crank Lift System. System Static force required to lift Torque required to lift a load in ewton () a load (m) Lever Lift System Quick-return crank Lift System Min: 5.80 Max: Min: Max: Conclusion In this research, a novel desin for a liftin jack driven by a quick-return crank mechanism and ear drive has been desined and fabricated. The desin equations for ear selection, ear drive ratios and mechanism forces have been derived from its eometry. Kinematic analysis has been performed. A desin example has been iven for illustratin the desin process. The detailed workin diaram has been explicitly explained equally. To verify the feasibility and accuracy, a prototype has been made, and then an experiment has been conducted. The proposed mechanism is capable of increasin capacity; reducin input effort; savin cost of operation and requires simple maintenance compared to conventional lever lift mechanisms of liftin jacks. The experimental result shows that Very little effort (5.80 minimum and maximum) and torque (0.597m and 51.38m maximum) is required to lift a load usin the modified screw jack compared with the classical method which requires effort of 17.4 and torque of m. Also, the time required to lift a car usin the modified method is lesser (.05s) compared to the time required to lift same weiht of car usin the traditional method (4.094s). Conclusively, the modified desin provides a ood alternative to the lever lift mechanism as other existin conventional liftin jacks require more effort, capacity, power eneratin sources and maintenance cost. The proposed quick liftin jack prototype was made up of a ear drive and a quick-return crank mechanism. References [1] A.S. Akinwonmi, A. Mohammed, Modification of the existin desin of a car jack, Journal of Emerin Trends in Enineerin and Applied Sciences. 3(4) (01) [] R.G. Budynas, J.K. isbett, Mechanical enineerin desin and advanced strenth and applied stress analysis, McGraw-Hill, Vol. 10, 008, pp [3] R.S. Khurmi, J.K. Gupta, Textbook of Machine Desin, Eurasia Publishin House, Ram aar, ew Delhi, India, 005. [4] I.S. Rout et al., Desin and fabrication of motorized automated object liftin jack, IOSR Journal of Enineerin. 04(05) (014) 6-1. [5] K.R. Mounika, C.H. Priyanka, Desin and fabrication of motorized screw jack for four wheeler, A Project Report, Department of Mechanical Enineerin, Gokaraju Ranaraju Institute of Enineerin and Technoloy, 011. [6] C.A. Okoronkwo et al., Desin of a hand water pump usin a quick-return crank mechanism, African Journal of Science, Technoloy, Innovation and Development. 8(3) (016) [7] S. Chaudhary et al., Development of motorized car jack, Journal of Applied Mechanical Enineerin. 5 (016) 16. [8] M.. Kumar et al., Desin and fabrication of screw jack usin worm ear, International Conference on Systems, Science, Control, Communication, Enineerin and Technoloy, 016, pp [9] R.K. Rajput, A textbook of enineerin thermodynamics, irewall Media, 010.

12 50 Volume 13 [10] M.A. Parker,. Pickup, Enineerin drawin with worked examples, Third Edition, Vol. 1, Hutchinson, ew Delhi, 1976, pp [11] J.M. Gere, Mechanics of materials, Thomson, 6th Edition, 006. [1] R.K. Rajput, Thermal enineerin, Laxmi Publications, 010. ISB: [13] C.W. Ham, D.G. Ryan, Experimental investiation of the friction of screw threads, Bulletin 47, University of Illinois at Urbana Champain, Collee of Enineerin, Enineerin Experiment Station, 193. [14] R.G. Budynas, J.K. isbett, Shidley s mechanical enineerin desin, McGraw-Hill Education, ew York, 011. [15] S.R. Patel, D.S. Patel, Dynamic analysis of quick return mechanism usin MATLAB, International Journal of Enineerin Science and Innovative Technoloy. (3) (013)

Design, Construction and Testing of an Electric Powered Toggle Jack Mechanism

Design, Construction and Testing of an Electric Powered Toggle Jack Mechanism Ipilakyaa T.D. 1, Achirgbenda V.T. 2, Gbashi S. 3 1Department of Mechanical Engineering, University of Agriculture Makurdi,