Design and construction of a quick return device for. With the quality, the noncutting point of mechanical reverse stroke can be shortened to improve work performance. The shaper machine involves two theoretical concepts of machine designing i. Shaper consists of a hollow machine bed made of cast iron which rests on the ground. For example, ham, crane and rogers 8 described its use as a crank shaper. Quick return motion mechanisms are used on machines tools to give slow cutting stroke and a quick return stroke for a constant angular velocity of the driving crank and arc combinations of a simple linkages such as fourbar linkages and the slider crank mechanism. Quick return mechanism, shapers, parallel misalignment, time ratio. As the ram moves at a faster rate during return stroke, the time taken becomes less. Specialized mechanisms whitworth quick return mechanism. This mechanism is used in tools, packaging and transport machinery. This mechanism is mostly used in shaping machines, slotting machines and in rotary internal combustion engines.
A usual shaper machine operates by a principle of whit worth quick return mechanism where materials are processed at one end and other end remains idle. Notice that the crank member 2 is rotating counterclock wise in this case and that the follower member 4 of the driving mechanism the inverted slider crank oscillates between two. Pdf mechanics of machinery i tareq shaban academia. The most common quick return ratio of the time of the cutting.
The cutting speed depending upon the type of material and machining condition whereas during the return idle return time. A crank and slotted lever mechanism used in a shaper has a centre. Quick return slider crank mechanisms have been used since the nineteenth century in a. Torque required to accelerate a mass at e is output in this inverse dynamic app.
Dec 05, 2020 the cutting speed depending upon the type of material and machining condition whereas during the return idle return time. Here an additional link couples the follower to a slider, usually a cutting tool. A quick return mechanism is also known as crank and slotted lever quick return motion mechanism. Quick return mechanism explore mechanical expressions. Crank shaper quick return mechanism whitworth quick return mechanism draglink quick return mechanism. A quick return motion mechanism is used in the shaper and slotter machine in which the circular motion is converted into reciprocating motion so that the slider moves forward and backwards. An offset slider crank mechanism the radius of the crank and length of the slider are important factors to consider when designing a quick return mechanism. The tool single point is reciprocating in motion equal to the length of the stroke and the work is clamped in position on an adjustable table. In construction, the crank shaper employs a crank mechanism to change the circular motion of a. Theoretical study and computer simulation of a modified quick. Here, the connecting rod is the frame, which is fixed. A thesis in mechanical engineering the requirements. An air compressor converts electrical energy in to kinetic energy in the form of air which is held in a highly compressed form before release. The crank and slotted lever quick return mechanism converts the rotary motion.
A presentation on the whitworth quick return mechanism, that covers the. Draw an alternative mechanism or combination of mechanisms that will produce the same forwards and backwards motion. This mechanism is called slotted lever quick return mechanism and it drives a horizontal ram which reciprocates in the guide ways provided on the top surface of the machine frame. For light cuts and finer feed, the shaper is appropriate whereas, for heavier cut and coarse feed, the planer is required. Generally, the shaper runs on a quick return mechanism whereas the planer runs on a gear mechanism or hydraulic device. Notice that the crank member 2 is rotating counterclock wise in this case and that the follower member 4 of the driving mechanism the inverted slider crank oscillates between two extremes. It is extensively used in shaping and cutting machines and is. The total machining time decreases and the rate of production increases. Quickreturn mechanism revisited american society for. Balancing weight are to be added to these linkages to avoid vibrations. This video tutorial will be very helpful to our engineering students. Quick return mechanism may be described as follows quick.
Pdf quick return mechanism design and analysis projects. Design fabrication and analysis of crank and slotted. Shaper machine can be broadly categories into the following. Hydraulic fluid is used in hydraulic quick return mechanism for the movement.
Whereas in the return stroke, the slider moves faster than the forward stroke that means quick return, it takes less time to return, called a return stroke. Sandor and erdman 9 gave an example of its use in connection with a flow metering pump. Whitworth quick return mechanism pdf download squarespace. In this tutorial we will be learn shaper crank and slotted link mechanism. Additionally, the device allows for easy changing of the time ratio. How quick return mechanism work best 3d animation crank. Apr, 2018 the return stroke occurs when the crank rotates from the position cb2to cb1 or through an angle alpha in the clockwise direction 4.
This mechanism is known as the quick return mechanism. This quick return is incorporated in almost all types of shaper. A quickreturn mechanism is a subclass of a slider crank linkage, with an offset crank. In this machine, the workpiece metal is removed during the return stroke of the ram. Is your new mechanism an improvement on the crank and slider mechanism. In the forward direction, the cutting process occurs while in return there is no such cutting. A quick return motion mechanism is used in the shaper and slotter machine in. A quick return mechanism is an apparatus to produce a reciprocating motion in which the time taken for travel in return stroke is less than in the forward stroke.
It consists of 3 turning pairs and one sliding pair as shown below. Chapter 1 introduction of mechanisms and machines darshan. Figure 11 quick return mechanism of shaper machine types of shaper machine. Crank slider mechanism crank slider mechanism is an arrangement of mechanical parts designed to convert straightline motion. The sixbar quick return mechanism is broadly used in manufacturing industries, like slotted link shaper machine, such type of machine sustain varying load during the manufacturing the job. The slider on the rocker arm which is also connected to the frame is the piston. The shaper machine used in lathe workshops works on the principle of whitworth quick return mechanism as shown in fig 1. Design and construction of a quick return device for use. Specialized mechanisms whitworth quick return mechanism quick return crank mechanism technology student. Quick return mechanism, cad model, position analysis introduction a quick return mechanism is a mechanism that converts rotary motion into reciprocating motion at different rate for its two strokes, i.
The link 3 corresponds to the connecting rod of a reciprocating steam engine. Design a fourbar quick return mechanism to provide a time. Explain various inversion of a slider crank mechanism with the help of. The shaper holds the single point cutting tool in ram and workpiece is fixed in the table.
Explain with the diagram working of crank and slotted. The article deals with kinematic analysis of quick return mechanism that is executed by. Oct 20, 2020 the sixbar quick return mechanism is broadly used in manufacturing industries, like slotted link shaper machine, such type of machine sustain varying load during the manufacturing the job. Though the lengths of both the forward and return strokes are equal, the ram travels at a faster speed during the return stroke. Design and construction of a 6 bar kinematic quick return. Shaper machines and its types page 1 shaper and types of shaper machines the shaper machine is a reciprocating type of machine basically used for producing the horizontal, vertical or flat surfaces.
Pdf quickreturn mechanism design and analysis projects. Mechanism synthesis in achieving thelps his goal in fewer steps. These both desired properties are obtained in all mentioned mechanisms. Inside the hollow portion the machine drive mechanism is housed.
In shaping machine, the half revolution of crank produces forward stroke and another half revolution of the crank produces return stroke. Three views on kinematic analysis of whitworth mechanism of a. So what happens in quick return motion mechanism is, in the forward stroke, the slider moves fast and removing the material from the workpiece. A quick return mechanism is an apparatus to produce a reciprocating motion in which the time taken for travel in one direction is less than in the other. Slider crank mechanism is usually found in reciprocating steam engine. The impacting press drive comprises a whitworth quick return mechanism consisting of a crank and a drive arm together with a variable speed d.
It consists of 3 turning pairs and one sliding pair as shown. In the quick return mechanism, a circular movement like the crank and lever. The speed of the bull gear is changed by the different. The most common quick return ratio of the time of the cutting stroke to the time of the return stroke is about 3. A crank shaper is comprised of a tool driven by an inverted slider crank. A novel design for quick return mechanisms, where the new mechanism is composed by a generalized oldham coupling and a slider crank mechanism is proposed in 6. It is driven by a circular motion source and uses a system of links with three turning pairs and a sliding pair. Apr 15, 2017 therefore, in order to reduce total machining time, the shaper mechanisms should be designed the quick return mechanism of a machine can e obtained by the following methods. For the model to be considered a quick return the desired time ratio should determine the radius of the crank and the length of the slider. Double parallel crank universal drafting mechanism double crank mechanism is a widelyused fourbar linkage, which boasts the same quick return movement features as the crank rocker mechanism. The whitworth mechanism is also known as the quick return mechanism. Jan 10, 2021 shaper machines the smaller jobs whereas planer machines heavier jobs.
In the shaper machine, there is another mechanism called quick return motion mechanism. These are usually obtained by following the four types of shaper machine mechanisms. This is an application of the oscillating cylinder mechanism. The quick return is a mechanism with numerous industrial applications, such as the shaper mechanism shown in figure 1. Shaper machine types, parts, working, operations, diagram. Design and construction of a quick return device for use as a. As per the requirement of a shaper machine, the velocity of forward and return strokes must be different. The depth of the cut increments by moving the workpiece, and the workpiece is fed by a pawl and ratchet mechanism. A thesis in mechanical engineering the requirements for in. The reciprocating movement of the ram and the quick return mechanism of the machine. Crank slotted lever quick return mechanism ppt getreport in.
Draw a diagram of the shaping machine and explain how the quick return mechanism works. The crank and slotted quick return mechanism converts rotatory motion into linear motion. Types of quick return mechanism there are three types of quick return mechanism 1. Therefore, the purpose of this project is to synthesize quick return mechanism that converts rotational to translational motion.
The crank length of a crank shaper is less than the base length o 2 to o 4 of the mechanism. Video link featured video shaper quick return simple alternative. Several quick return mechanisms can be found in the literatures, including the offset crankslider mechanism, the crank shaper mechanisms, the double crank. But in a dual side shaper machine, materials are processed at both ends which become advantageous when compared to usual shaper. It represents a revolving crank slider and produces nonuniform stroke movement with slow forward movement and fast backward movement. The following mechanisms are used for quick return of the ram. The mechanism consists of a slider, crank, fixed link, slotted lever, connecting rod and ram. Quick return mechanism consists of many linkages that rotates at high speeds. This pinion receives its power from the individual motor. The mechanism analyzed here is a quick return one which has numerous industrial applications. The whitworth quick return mechanism has been modified and used for constructing highvelocity impacting press. In the quick return mechanism, a circular movement like the crank. If you havent read about the shaper machine mechanism you can read here.
Shaper machine process the shaper process can be defined as a process for removing metal from the surface in horizontal. The reciprocating movement of the ram and the quick return mechanism of the machine are usually obtained by any one of the following methods. Types of quick return mechanism mechanism in shaper. Three views on kinematic analysis of whitworth mechanism. The crank and slotted link mechanism of a crank type shaper converts the rotation of an electric motor into the reciprocating movement of the ram. The main parts of the shaper machine is base, body pillar, frame, column, cross. Application of whitworth quick return mechanism for high.
A quick return mechanism such as the one seen below is used where there is a need to convert rotary motion into reciprocating motion. Whitworth mechanism a quick return mechanism is a mechanism which produces a reciprocal effect so that the system takes less time in the return stroke while comparing with forward stroke. Our machine is a crank shaper quick return mechanism designed to run at low speed, to highlight the differences between front and back strokes. The return is governed by a quick return mechanism. A quick return motion mechanism is useful in all such applications, 1. In the crank and slotted link mechanism, the power is transmitted to the bull gear through pinion. Quick return is a common feature of tools in which the action is performed in only one direction of the stroke, such as shapers and powe. Several procedures were devised for selected mechanisms to help designers in the synthesis process, this includes the slider crank, fourbar, crank shaper, point and threetwo point mechanism which will be discussed in this chapter. The crank and slotted link mechanism is discussed as under. Apr 14, 2020 in shaper, rotary movement of the drive is converted into reciprocating movement by the mechanism contained within the column of the machine. In a standard shaper, cutting of material takes place during the forward stroke of the ram and the return stroke remains idle. Explain with the diagram working of crank and slotted lever. Multiplechoice questions or objective questions on shaper. Crank and slotted lever quick return motion mechanism.
159 293 428 1501 677 164 906 913 884 1109 1011 1056 1310 747 1424 1483 690 1329 1169 1592 1036 571 1318 90 985 743 1274 1610 352 963 699