The construction industry has a long Turn Around Time (TAT) due to human- based work environment. Further, lack of skilled labour, increase in labour cost, and technological advances are forcing rapid changes in building construction, which mainly consists of commercial infrastructure and residential building, where plastering work is must. The introduction of a new automated plastering machine can help to reduce the TAT in the construction field. The present work developed a model of a wall plastering machine. The proposed machine consists of an AC motor, gear box, wire rope mechanism, pulley, hopper-tray, guide ways, etc. The model has been fabricated considering a normal constructed brick wall, and further validated through testing in real-time environment.
Wall Plastering Machine Pdf 11
Each employee performing overhand bricklaying operations from a supported scaffold shall be protected from falling from all open sides and ends of the scaffold (except at the side next to the wall being laid) by the use of a personal fall arrest system or guardrail system (with minimum 200 pound toprail capacity).
When concrete is chipped using grinders dust and concrete particles are scattered everywhere and this causes health issues. Most common site injuries from the use of angle grinders are to the head and face. According to an analysis conducted by Carter et al. [5], they have shown that the usage of angular grinders to chip concrete surfaces leads to severe accidents, especially to the head and face. Concrete breakers, on the other hand, can damage the whole concrete structure and reinforcement because of its high vibration and also affect the operator using the concrete breaker machines, some effects are, lower back pain, motion sickness, bone damage, high blood pressure due to vibration and respiratory metabolic change and on the other hand, use of heavy hand tools is exhausting and time-consuming. Therefore these machines and methods that are currently in use are quite inconvenient for chipping concrete.
In order to provide a machine that would eliminate or reduce the above risks, health effects and time, several designs were proposed and an attachment for the grinder was selected to be the most suitable out of the proposed designs. Initially, to design the attachment, the basic parameters had to be calculated and for that several boundary conditions were defined according to the standards laid out on chipping concrete. After designing the attachment, the 3D model was designed using SOLIDWORKS and a simulation was carried-out by ANSYS in order to determine the stress distribution of the tool and its failure on the application of load.
Several designs with different mechanisms, such as linear motion, crank-slider mechanism, worm and wheel mechanism, and cam and follower were used in the design of different concrete chipping machines. The different design ideas for the chipping machine were drafted and their drawbacks were listed in order to select the most applicable design. Various factors were considered to determine the most suitable design for chipping concrete. The factors considered were;
When compared with one another, several drawbacks such as design complexity, balancing, maintenance and etc. were found. Therefore, it was decided to go ahead with an attachment to the grinder machine.
The parameters such as the diameter, length, weight of the pointed tool were taken into account to determine whether it was possible to provide the minimum force required to penetrate the concrete wall at a given speed of revolution of the cam plate. Thus, the tool was selected giving priority to the overall weight addition and the force produced at an average speed of rotation of the cam plate (1700 rpm was considered). The selected standard tool was HS1814, a pointed tool made of high-speed steel. In order to determine the stress distribution and failure of the tool during impact at the minimum required force of penetration, a simulation was carried out using ANSYS. It was found that the tool did not fail at the minimum required force of penetration; therefore the standard tool HS1814 made of high-speed steel was selected for prototyping. The dimensions and parameters of cam-plate, springs, cover for attachment, welded joints, bolt and etc. were calculated subsequently [9]. Sections 3.1 and 3.2 provide the methods and standards used to calculate the surface hardness of concrete and design the cam profile of the cam plate.
Simulations were carried out using ANSYS explicit dynamics solver to determine the penetrability of the tool and the stress concentration of the tool during impact. It was found that the designed tool could penetrate more than 3 mm (standard depth of penetration) of the concrete wall. For the simulation, a portion of the tool and wall was used with medium-sized mesh. Figure 7 shows the stress concentration of the tool and Fig. 8 shows the graph of penetration versus time.
The attachment to the grinder machine contains a handle (1) which can be used by the operator to hold the grinder and to prevent the reaction force due to impact. This handle is attached to the grinder (2), which already had a threaded hole, using a threaded bolt (3). The attachment contains a cam plate (4) which is fixed to the threaded bolt of the grinder itself. The cam plate consists of two cam lobes to which two pointed tools (5) are in constant contact using two restraining springs (6). The two pointed tools are guided through a tool guider (7) and two plates (8, 9). These components are covered by the housing (10) which at the end has an adjustable portion in order to adjust the depth of penetration. It also contains a scale which the operator can use to adjust the depth of penetration to a least count of 0.5 mm. Figure 11 shows the exploded view of the prototype and Fig. 12 shows the assembled machine without housing and with the housing. All components of the attachment to the grinding machine, mentioned from (1) to (11) were manually designed and materials were selected accordingly.
Comparatively, the prototyped concrete chipping machine (an attachment to the grinding machine) has advantages with respect to price, power, and weight as shown in Table 6. A survey was conducted on the use of different machines utilized to chip concrete in the construction industry and the prototype concrete chipping machine. Following analysis shows the summary of the data collected from the survey;
A questionnaire was carried out for a sample of 30 personal, working in the construction industry, and the following facts were concluded. The remarks of the employee about time consumption, easiness, weight were positive. Some have had suggested improving the machine so that the size of the tool can be varied.
It was found that the prototype developed was slightly noisy although the other aspects are comparatively better than the machines available in the market, thus improvements in this aspect have to be done in the future.
Concrete chipping is a process carried out in order to increase the adherence of the concrete and the mortar before the plastering process. Machines available in the market had several issues, thus a new design was introduced. With the new machine, the following goals were achieved:
On a survey carried-out using the prototyped concrete chipping machine at several construction sites, it was found that, an approximate time saving of 55% can be achieved, when compared with other hand tools.
ANSYS software can be used to determine the stress distribution before the machine is prototyped. This gives the designer an idea of the necessary changes that have to be made before prototyping, thus reduced wastage of time and money. The attachment to the grinder would be a suitable inclusion to chip concrete. Unlike the use of hand tools, concrete breaking machines, angle grinders with grinding discs, and the grinding machine with the attachment (concrete chipping machine) have proven to be a lot safer to use, efficient and less time-consuming. Further improvements of this machine would be to reduce the weight of the attachment and to develop various replaceable sizes of the attachment (with different tool sizes) to facilitate the operator to change the attachment depending upon the surface it is being used. 2ff7e9595c
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