Square Drill

ABSTRACT

Producing square holes in the industry, is very common and useful and at the same time along with problems such as high cost and complexity of manufacture.Using a drill with n on-coaxial couplings, in addition to easier manufacturing, also reduces the costs of  production. A mathematical mathematical model for drill drill mechanism has been been proposed in the first first part of this paper. The mechanism of the drill and cam is designed by using the mathematical model. The main limitation of the square hole drilling mechanism is cam center of rotation, where it is not fixed and moves in a non-circular path. There is thus a need to non-coaxial couplings, in order to transmit rotational motion, made by drill to cam and  bit. Examples of non-coaxial couplings are Richard Schmidt, Oldham and Universal couplings, which this paper was to examine the universal couplings.

KEYWORDS: KEYWORDS: Reuleaux Polygon, Square Hole, Universal Couplings, Edm Machining, Curves Of Constant Width

Square holes are used widely in industry. Examples of these applications are used in some of the couplings. Since the square shape of the hole and shaft, will lead to full involvement of couplings, accordingly prevent freewheeling.

There are a variety of methods for creating square holes. One of these methods is making a square hole by CNC machine. Using CNC machine, despite the high accuracy, costs too much. In this method, the hole plan on workpiece, designed by CAD softwares, and then after  becoming to G-Code, it transferred to CNC machine (Alan Overby, 1986). Another method is to use an Electrical Discharge Machine Machine (EDM). EDM is a process that uses electrical discharges from an electrode to erode an electrically conductive material (Ben Fleming, 2005), regardless of the mechanical properties such as strength and hardness. In this machining method, the electrode is constructed to the shape of desired hole and by creating electrical discharge  between tool electrode and workpiece, the spark is generated and the shape of electrode on workpiece caused (K.Y. Song et al., 2013). It should be noticed that no physical contact  between the tool electrode electrode and workpiece workpiece is created created in the EDM method. method.

Broaching machining method is another metho d that can be used to create square holes on workpieces. Broaching is commonly used for machining of internal or external complex  profiles that are difficult to generate by other machining processes such as milling and turning. Originally broaching was developed for non-circular internal profiles, such as square hole and keyways (U. Kokturk and E. Budak, 2004). Square hole drilling mechanism, including a tri angle-like cam that can have rotational motion within a square frame. To investigate the

mathematical model for the cam , a discussion called Curves of Constant Width is propose d. Curves of constant width provide a great example of vec tor space and also allow us to gain access to a large amount o f information. In particular, Reuleaux polygons, a special set of curves of constant width give unexpected results to prac tical questions; such as drilling a square hole (Peter Fumich et al, 1987). The existence of non-circular curves of constant width in the standard Euclidean plane has been known since the time ofEuler; e.g., the Reuleaux triangle was presented by Reuleaux

toHornblower,

the

inventor

of

the

compound

steam-engine

(Horst

Martini

and

ZokhrabMustafaev, 2008). Inrecent years, mathematical properties of the R euleaux triangle have led to some very important application s. Since a curveof constant width can be freely rotated in a square always maintaining contact to all four sides of the square, a Reuleauxtriangle Reuleauxtriangle can be used for drilling holes of maximum area into squares.Reuleaux polygons are formed by connections through non-uniform circular arcs to each other (Kupitz, Y.S. and Martini, H., 2000).Some Reuleaux curves are shown in fig. 1. The curves of constant width have a plane shape with a constant width in all directions.The proposed term, width, is a vertical distance  between the t wo parallel lines tangent tangent to curve.

Figure 1. Curves of constant width

The square frame which the cam rotates inside it is fixed to the body of the drill.As long as the ca m is rotated 360 degrees, the whole inner surface of square frame is covered by cam rotation inside the square frame. Accordingly, if a bit is designed on the cam, it could b e able to cover entire square surface and do milling in a square shape. Off-axis couplings transmit torque  between two o ff-axis shafts. For instances Richard Schmidt coupling (fig. 2 ), Oldham coupling (fig. 3), and Universal coupling or Hook coupling (fig. 4) are noted. The inventor of the coupling, Richard Schmidt of madison, Alabama, said that a similar link arrangement had  been known to some German engineers for years. But those engineers were discouraged from applying the theory because they erroneously assumed that the center disk had to be retained by its own bearing. Actually, Schmidt found that the center disk is free to assume its own center of rotation. In operation, all

1

Correspondi

ng author

three disks rotate with equal velocity (Neil Sclater and Nicholas P. Chironis, 2007).

In Oldham coupling, it should be noticed that it can be proved all three disks rotate with equal rotational velocity, and thus the rotational velocity of driver shaft and driven shaft will be equal (Yutaka Nishiyama, 2009).

Figure 2. Richard Schmidt coupling

Figure 3. Oldham coupling

Figure 4. Universal coupling

A mathematical model used for cam mechanism is provided in the first part of this paper. In the second part, the universal coupling used for transmitting torque from drill to cam, has been studied.

MATHEMATICAL MODEL FOR THE CAM

Equations have been derived based on the simplest curves of constant width, the circle. According to fig. 5, width of curve calculated by the equation:

h(t)  h(t π  )  k

(1)

Where h shows perpendicular line to drawn tangent to the curve, t is the angle between h line and horizontal axis and k is a constant. Family of tangents is obtained from equation:

F(x, y,t) x.cos t y.sin t − h(t)

(2)

Figure 5.circle, simplest curve of constant width

To find envelope of this family, we use the equation (Andrew David Irving, 2006):

F

∂F

 0



(3)

∂t

x and y are measured in terms of the parameter t, using equations 2 and 3:

x(t)  h(t).cost − h′(t).sin t (4) y(t)  h(t).sin t  h′(t).cost

By choosing h(t) to different forms, variety curves of constant width equations are obtained. It should be noted that h(t), should satisfy equation 1. For example by choosing h(t)=1, equation of the simplest curves of constant width, the circle is

3 obtained.By choosing h(t)a.cos

t )  b , curve ( width 2

would be equal toa+2b(Andrew David Irving, 2006) (Stanley Rabinowitz, 1997). Ifa=2 and  b=8, then:

x(t)  (cos3t  9).cost  3sin 3t.sin t (5) y(t)  (cos3t  9).sin t − 3sin 3t.cost

The diagram of equation 5 is plotted in fig. 6, using the software, maple, which has shown the

 profile of cam curve.

Indian J.Sci.Res.1(2) : 583-586, 2014 584

Figure 6.diagram of cam curve

1.Universal couplings for torque transmission

In square hole drilling mechanism, the cam center of rotation, is not fixed and is displayed in a non-circular path. Due to this, a non-coaxial coupling should be used for torque transmission. The universal coupling is one of the most widely used of non-coaxial couplings, which has the ability to transmit torque between parallel and non-parallel shafts and is composed of two universal joints. The joint was used on the clock mechanism for the first time at 1352 AD. th

Figurre 7 shows the universal joint, which is designed in the 16  century and is maintained in Deutsches museum in munich( H.Chr. Seherr-Thoss et al., 2006).

Figure 8. Universal joint anngles in schematic form

Figure 9. The ω2 ⁄ω1r atio diagram in φ1

The driven shaft acceleration is also calculated from equation:

2

cosβ .sin

2

2φ 1

β .sin

(1− 2



ω 1

2

2

sin β .sin φ 

)2

8

1

In the case shown in fig. 10, if two Universal joints are used in doubled mode, the Universal coupling is caused, which is capable to transmit torque between off-axis shafts.

Figure 10. The universal coupling, made of successive connection of two universal joints

In Universal coupling, the relation between rotational angle of driver shaft,,and rotational angle of driven shaft, ,is expressed in equation:

1.tanφ 1

cos

tanφ  3

9



cos

2

In case which driver and driven shafts are off-axis, then, and therefor the rotational velocity of driver and driven axes are equal. CONCLUSION

Triangular cam profile is obtained from equation 10, which can be rotated within a square frame. So if the bit is mounted on the cam, it can make a square hole (fiq. 11).

Figure 11. The cam and the bit mounte d on it

Because the cam center of rotation is not fixed, universal couplings are used to transmit torque.Unlike the universal joints, which rotation velocity of driver and driven shafts are not equal, in universal couplings the driver and driven velocities are equal. And therefor these kinds of couplings are more appropriate to transmit torque from drill to cam.

Circular motion can be converted into a four-sided square using the Reuleaux triangle. The process relies on the property of Reuleaux triangle’s diameter being

consistent across all points, and when rolled and rotated simultaneously, tracing a square area with slightly rounded corners. By slightly altering the shape of the triangle to mimic a drill bit (for cutting and extracting material), a drill with a specialized rotating chuck can create perfect, four-sided holes. These drills were pioneered by Harry Watts, and can still be found today, albeit not at your typical home improvement store.

The following is a bit of literature that helps explain and illustrate the concepts behind the Reuleaux triangle. Please check out more of Prof. Smith’s work here. Drilling Square Holes

by Scott Smith published in The Mathematics Teacher, October 1993 (Volume 86 Number 7)  A bit that drills square holes … it defies common sense. How can a revolving edge cut anything but a circular hole? Not only do such bits exist (as well as bits for pentagonal, hexagonal and octagonal holes), but they derive their shape from a simple geometric construction known as a Reuleaux triangle (after Franz Reuleaux, 1829-1905).

To construct a Reuleaux triangle, start with an equilateral triangle of side s (Figure 1). With a radius equal to s and the center at one of the vertices, draw an arc connecting the other two vertices. Similarly, draw arcs connecting the endpoints of the other two sides. The three arcs form the Reuleaux triangle. One of its properties is that of constant width, meaning the figure could be rotated

completely around between two parallel lines separated by distance s. It was with this property of constant width that the Reuleaux triangle was introduced in a sidebar of our geometry text (Moise and Downs, Teachers’ Edition, p. 555). ―This figure has constant width,‖ I lectured, ―just like a circle.‖ Without thinking, I volunteered, ―Imagine it as wheels on a cart.‖ ―What sort of cart?‖  ―Why, a math cart, to carry my board compass and protractor,‖ I replied, digging myself in deeper. This was the first of several impulsive misstatements I made about the Reuleaux triangle, only to admit after a little reflection that it wasn’t so. Not in twenty years of teaching had my intuition failed me so completely.

The constant width property can be used to transport loads, but not by using Reuleaux triangles as wheels. If several poles had congruent Reuleaux triangles as cross sections, bulky items could ride atop them (Figure 2). Movement would occur as poles were transferred from back to front, providing a moveable base of constant height.

But the Reuleaux triangle cannot be a wheel. The only conceivable point for the axle, at the triangle’s centroid, is not the same distance from the Reuleaux triangle’s ―sides‖ (Figure 3). If the sides of the equilateral triangle are s, then 2

ssqrt(3)

(1) 3

2

AP = -

-sqrt(3) = ------- s » 0.577s, 3

while sqrt(3)

sqrt(3) PB = s - ------- s = s(1 - -------) » 0.423s. 3

3

Even if four Reuleaux triangle wheels were synchronized, the load would rise and fall continuously — you’d need Dramamine to ride this cart!

 ―And since it has constant width, it would just fit inside a square whose sides are that width,‖ I continued, trying to regain their attention. I carefully drew a square circumscribing the Reuleaux triangle (Figure 4). The triangle is normally tangent to two sides of the square with two vertices touching the square directly opposite the points of tangency (why?), as in Figure 4a. The exception is Figure 4b, where the Reuleaux triangle has one point of tangency and all three vertices on the square (one directly opposite that point of tangency).  ―If the Reuleaux triangle just fits inside the square, no matter what position it’s in, couldn’t it rotate around the inside of the square?‖ They needed convincing — a

model would have to be built. ―But if it did rotate around the inside, doesn’t that mean that a sharp Reuleaux triangle could carve out a square as it rotated?‖ I had them. ―Drill a square hole?‖, one countered. ―No way!‖ 

That night I cut a four inch Reuleaux triangle from a manila folder to take to class the next day. With a lot of effort, I was able to show the triangle rotate around the inside of a four inch square. ―And if this was metal at the end of a rotating shaft, it would cut out a square‖, I continued, racking up two more falsehoods. Firstly, it was implied that the center of the Reuleaux triangle would coincide with the center of a drill’s shaft; it cannot. And secondly, the corners of the holes are not right angles, but slightly rounded.

Trying to show the triangle should be centered at the end of a rotating shaft, I stuck a pen through the triangle’s center which, while a student manually rotated the triangle within the square, traced the center’s path on paper beneath (Figure 5). ―It’s definitely not a single point,‖ I had to admit, holding up the traced curve,

 ―but it sure looks like a circle!‖ Falsehood #4.

Just what is the path of the centroid of a Reuleaux triangle boring a square hole?  Assume the square and the equilateral triangle have sides of length 1. Center the square about the origin and position the Reuleaux triangle so vertex A is at (1/2,0), as in Figure 6a. Using (1), the triangle’s centroid will be P (1/2+sqrt(3)/3,0). Now imagine rotating the triangle clockwise through the position in Figure 6b, and ending up in Figure 6c, where the centroid is P‖(0,1/2+sqrt(3)/3). The path from P to P‖ lies in quadrant I. Let a be angle MA’B’, ß the angle formed by A’P’ and a horizontal line through A’, and c the y -coordinate of point A’. We are interested in the coordinates of P’. Note that cosa=1/2+c and that ß=270°+a+30°=300°+a. Also note that during this rotation, a goes from 60° to 30°. Because A’P’=sqrt(3)/3, if we measure from the coordinates of A'(-1/2,c), the x and y coordinates of P’ can be found. -1

sqrt(3)

-3 + sqrt(3) cos(a) + 3

sin(a) (2)

x = - + ------- cos(300°+a) =

-----,

-------------------------

2

3

6

and sqrt(3) (3)

y = c + ------- sin(300°+a)

3

sqrt(3) = (cosa – 1/2) + ——- sin(300°+a) 3

-3 + 3 cos(a) + sqrt(3) sin(a) = —————————— 6

as a goes from 60° to 30°. Finding the path of the triangle’s center in the other three quadrants is similar in procedure and produces equations symmetric to the origin and both axes. 3 - sqrt(3) cos(a) - 3 sin(a) Quadrant II:

x = -----------------------------

6

-3 + 3 cos(a) + sqrt(3) sin(a) y = —————————— 6

3 – sqrt(3) cos(a) – 3 sin(a) Quadrant III: x = —————————– 6

3 – 3 cos(a) – sqrt(3) sin(a) y = —————————– 6

-3 + sqrt(3) cos(a) + 3 sin(a) Quadrant IV: x = —————————— 6

3 – 3 cos(a) – sqrt(3) sin(a) y = —————————– 6

But these equations do not describe a circle. In equations (2) and (3), when a=30°, P is on the x-axis at approximately (0.07735,0). But when a=45°, -6 + sqrt(6) + 3sqrt(2) x = y = ------------------------, 6

which makes the distance from P’ to the origin about 0.08168. This non-circularity is also shown by graphing the four parametric equations above with a circle whose radius is slightly smaller or larger. In Figure 7, the circle is the outer curve. Notice

that the centroid’s path is farther from the circle at the axes than mid-quadrant.

So the Reuleaux triangle’s centroid does not follow a circular path. How then is the Reuleaux bit contained within the square outline it’s to cut? Harry Watts designed a drill in 1914 with a patented ―full floating chuck‖ to accommodate his irregular bits. Bits for square, pentagonal, hexagonal and octagonal holes are still sold by the Watts Brothers Tool Works in Wilmerding PA. The actual drill bitfor the square is a Reuleaux triangle made concave in three spots to allow for unobstructed

corner-cutting and the discharge of shavings (Figure 8).

Even the modified bit leaves slightly rounded corners. How rounded? Assume the starting position in Figure 9a, in which the Reuleaux triangle is just tangent at point C.  As the triangle rotates counterclockwise, C leaves that edge of the square temporarily (labeled C’ in Figure 9b) only to rejoin another at position C‖ in Figure 9c. In Figure 9b, let a be angle MA’B’, ß be the angle formed by A’C’ and the horizontal line through A’, and c the y-coordinate of A’. Then ß = a+60°-90° = a-30° and cosa = 1/2+c. To generate the corner by C, a starts at 30° in Figure 9a and ends up at 60° in Figure 9c. Using A’C’ = 1 and measuring from the coordinates of A’, the coordinates of C’ are described by -1 x = - + 1 cos(a-30°) =

-1 + sqrt(3) cos(a) + sin(a) ----------------------------,

2

2

and 1 y = c + 1 sin(a-30°) = (cosa - -) + sin(a-30°)

2

-1 + cos(a) + sqrt(3) sin(a) = —————————-. 2

The equations for the other three corners are similar, and when graphed with the rest of the square yield Figure 10. Not only does the Reuleauxtriangle have practical and interesting applications, and is easy to describe geometrically, but it generates a lot of discussion due to its nonintuitive properties. With this background, you can avoid the blunders I made. Further explorations into the topic might include other figures of constant width (see Gardner and Rademacher/Toeplitz); further identifying the curve of the Reuleaux triangle’s center as it cuts a square; and the shapes of bits for pentagonal, hexagonal and octagonal holes.

SYNOPSIS ON DESIGN AND FABRICATION OF SQUARE DRILLING TOOL

TITLE PAGE

CHAPTER - 1 INTRODUCTION

Drilling is a process of making a hole or enlarging a hole in an object by forcing a rotating tool called drill. The same process can be accomplished in some other machine by holding the drill stationary and rotating the work. The most common example of drilling in this class is drilling in a lathe, in which the drill is held in the tail stock and the work is held and rotated by the chuck.

Figure 1 Drilling Process Drilling machine is one of the simplest, moderate and accurate machine tool used in production shop and tool room. It consists of a spindle, which imparts rotary

motion to the drilling tool, a mechanism for feeding the tool into the work piece, a table on which the work rests and a frame. It is considered a single purpose machine tool since its chief function is to make holes. However, it can and does perform operations other than drilling also Specification of Drilling Machine (a) Portable drilling machine is specified by the maximum diameter of the drill which can be

held. (b) Sensitive and upright drilling machines are specified by the diameter of the largest work

 piece that can be drilled. (c) The radial drilling machine is specified by the length of arm and column diameter. (d) Multiple spindle drilling machine is specified by the drilling area, the size and the number

of holes a machine can drill Types of Drilling Machine Tools

A Drill is a fluted cutting tool used to originate a hole in a solid material. The types of the drills commonly used are: (a) Flat or Spade Drill: a flat drill is sometimes used when a same sized twist drill is not

available. It is usually made from a piece of round tool steel which is forged to shape and is ground to size, then hardened and then tempered. The cutting angle varies from 90 to 120 degree and the relief and clearance at the cutting edge is 3 degree to 8 degree. The disadvantage of this type of drill is that each time the drill is ground the diameter is reduced. Another difficulty of this type of drill is that the chips do not come out of the hole automatically. (b) Straight Fluted Drill: it has grooves or flutes running parallel to the drill axis. A

straight fluted drill may be considered as a cutting tool having zero rake. This type of drill is inconvenient in standard practice as the chips do not come out from the hole automatically. It is mainly used in drilling brass, copper or other softer materials. The straight fluted drill does not tend to lift the sheet as does the twist drill.

Figure 2. Straight flute drill bit (c) Twist Drill: the most common type of drill in use today is the twist drill. It was

originally manufactured by twisting a flat piece of tool steel longitudinally for several revolutions, then grinding the diameter and the point. The present day twist drill are made by machining two spiral flutes or grooves that run lengthwise around the body of the drill. Twist drill is an end cutting tool.

About Square Drill

A drill is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of the drill and rotated while pressed against the target material. Drills are commonly used in woodworking and metalworking. Specially designed drills are also used in medicine, space missions and other applications. Generally, the drill used most often is used to drill a round hole used for many products, machines, nut-bolts fastening, etc. But, there are many applications where drilling a square hole is required that could not be attained with general purpose round drill bits. However, if we are able to design a square drill, it would be very advantageous as it would reduce the overall time and equipments required in order to make a square hole from a round hole. So, this square drill is very suitable for designing of many products that require square hole. The aim is to design a mechanism for drill bit that would make a square hole by spinning around its axis. A mechanism for drilling square holes has to turn circular motion into square motion. Now the idea of using a spinning drill bit to create a square hole, as the figure below.

Figure 2: Square drill using Reuleaux triangle Like a circle, this rounded triangle fits snugly inside a square having sides equal to the curve's width no matter which way the triangle is turned. As it rotates, the curved figure traces a path that eventually covers nearly every part of the square.

Figure 3: Rotated inside a square, a Reuleaux triangle traces a curve that is almost a square

CHAPTER NO. 2 LITERATURE REVIEW 2.1 Reuleaux Triangle

A Reuleaux triangle is the simplest and best known Reuleaux polygon, a curve of constant width. The separation of two parallel lines tangent to the curve in independent th

of their orientation. The term derives its name from Franz Reuleaux, a 19  century German engineer who did pioneering work on ways that machine translate one type of motion into another.

Figure 4:- Construction of Reuleaux triangle 2.2 Construction

With the compass sweep an arc sufficient to enclose the desired figure. With radius unchanged, sweep a sufficient arc centred at a point on the first arc to intersect that arc. With the same radius and the centre at that intersection Sweep a third arc to intersect the other arcs. The result is a curve of constant width. Equivalently, given an equilateral triangle ‘T’ of side length r, take the boundary of the intersection of the disks with radius r centred at the vertices. The existence of Reuleaux polygons shows that diameter measurements alone cannot verify that an object has a circular cross-section. The area of Reuleaux triangle is smaller than that of the disk of the same width (i.e. diameter); the area of such a disk is( π/4)*r². 2.3 Area of Reuleaux triangle

Let the arc radius be r. Since the area of each meniscus-shaped portion of the Reuleaux triangle is a circular segment with opening angle (1)

(2)

But the area of the central equilateral triangle with a = r is (3) so the total area is then

2.4 Reuleaux polygons:-

Figure 5 Reuleaux polygons. The Reuleaux triangle can be generalized to regular polygons with an odd number of sides, yielding a Reuleaux polygon. 2.5 Reuleaux triangle rotating inside a square of unit length

When we rotate the Reuleaux triangle inside a square, its centroid doesn’t revolve at a fixed point, neither does it move along a circle.

Figure 6- Reuleaux triangle inside a square Its path is made up of four different arcs which lies separately in each quadrant.

CHAPTER NO. 3

PROBLEM FORMULATION

To design a mechanism for drill bit that would make a square hole by spinning about its axis as well as rotatory movement in the shape of Reuleaux triangle using floating drill chuck assembly. To drill the square hole in the wood, the drill must define the path of Reuleaux triangle’s centroid rolling inside a square. Need and significance

Generally, the drill used most often is used to drill a round hole used for many products, machines, nut-bolts fastening, etc. But, there are many applications where drilling a square hole is required that could not be attained with general purpose round drill bits. However, if we are able to design a square drill, it would be very advantageous as it would reduce the overall time and equipments required in order to make a square hole from a round hole. So, this square drill is very suitable for designing of many products that require square hole. A mechanism for drilling square holes has to turn circular motion into square motion. Now the idea of using a spinning drill bit to create a square hole Project was done Under guidance of Er. Tejinder Kumar , IISER Mohali sec-82 Mohali , 9988218772 , [email protected]

CHAPTER NO. 4 OBJECTIVES

Our objectives with this research work are: 1. To design a drill bit in the shape of reuleaux triangle for drilling square holes. 2. To design the drill chuck mechanism to produce the motion that could turn the drill bit in rotary as well as spinning motion on the basis of reuleaux triangle. Our design consists of following components: 

a reuleaux triangle drill bit revolving inside a square frame



shaft



universal joint



slip joint

3. To make the square drilling bed on which the tool will be tested after completion.

CHAPTER NO. 5 RESEARCH METHODOLOGY

The reuleaux triangle drill bit has the shape of reuleaux triangle and it is a elongated bar section. The straight flutes are cut on it. There will be three flutes cut on it, since this drill  bit will be having three faces. These flutes are provided on it in order to provide a path for the chips to escape through them. Only straight flutes are cut because the helical flutes can damage the profile of the reuleaux triangle drill bit. The straight flute drill bits although are less efficient to chip disposal than helical drills, but with the slight modification can serve the purpose. The figure below shows the geometry of reuleaux triangle drill bit.

Figure 8: Geometry of reuleaux triangle drill bit

Synthesis (mechanism)

To drill the square hole in the wood, the drill must define the path of reuleaux triangle’s centroid rolling inside a square. To perform this, our mechanism will provide just the kind of motion to the reuleaux triangle drill bit. Our design will consist of following components: 

a reuleaux triangle drill bit revolving inside a square frame



shaft



universal joint



slip joint Rotary motion is provided to the shaft with the help of some external means.

External means may be motor, engine or hand wheel which we have also used in our minor  project. The shaft is then connected to the one end of the flexible universal joint. Other end of the shaft is connected to the slip joint, which is connected to the reuleaux triangle which is rotating inside the square frame guide. The Reuleaux triangle just roll inside its guide and the guide is mounted on the frame. Reuleaux triangle then extends into a drill bit. When motion is provided to the hand wheel, the shaft starts rotating, transmitting power to the universal joint, slip joint and then to the drill bit but the point of  junction of shaft and reuleaux triangle does not rotate about a fixed axis. This point revolves in an eccentric pattern. Because of this, the transmitting shaft moves up and down and also undergoes change in length. With the help of flexible universal joint, power is equally transmitted from one shaft to the other at all angles and the problem of change in length is taken care of by the slip joint which permits the axial movement of the shaft on account of the eccentricity. So the drill bit is made to rotate in a way, which leads to the drilling of square hole.

CHAPTER - 6 FACILITIES REQUIRED FOR PROPOSED WORK

A mechanical workshop / Industry with following tools and equipments are required for doing the proposed work: 1. Electrical Discharge Machining (EDM)

2. Welding 3. Surface grinding 4. Wire cutting Machining 5. Lathe Machining 6. Drill Machine 7. Milling Machine

CHAPTER - 7 PROPOSED PLACE OF WORK

1. Mechanical Workshop in College 2. K.B. Tools and Equipments, E-93, Phase - 7, Industrial Area, Mohali

Rack & Pinion Arrangement  A rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. A circular gear called "the pinion" engages teeth on a linear "gear" bar called "the rack"; rotational motion applied to the pinion causes the rack to move, thereby translating the rotational motion of the pinion into the l inear motion of the rack. For example, in a rack railway, the rotation of a pinion mounted on a locomotive or a railcar engages a rack between the rails and forces a train up a steep slope. For every pair of conjugate involute profile, there is a basic rack. This basic rack is the profile of the conjugate gear of infinite pitch radius.[1] (I.e. a toothed straight edge.)  A generating rack is a rack outline used to indicate tooth details and dimensions for the design of a generating tool, such as a hob or a gear shaper cutter .[1]

 Applications[edit]

Lock gate controls on acanal

Rack and pinion combinations are often used as part of a simple linear actuator , where the rotation of a shaft powered by hand or by a motor is converted to linear motion. The rack carries the full load of the actuator directly and so the driving pinion is usually small, so that the gear ratio reduces the torque required. This force, thus torque, may still b e substantial and so it is common for there to be a reduction gear immed iately before this by either a gear or worm gear reduction. Rack gears have a higher ratio, thus require a greater driving torque, than screw actuators.

Rack railways[edit]

Rack railway axle

For more details on this topic, see Rack railway .

Rack railways are mountain railways that use a rack built into the centre of the track and a pinion on their locomotives. This allows them to work on steep gradients, up to 1 in 2 (50%), far in excess of those a conventional railway relying on friction can achieve.  Although the extra grip of the rack system is obviously important for climbing, it has perhaps a more important use in also allowing controlled braking on these steep lines and for being much less affected by snow or ice on the rails.  A rack and pinion with two racks and one pinion is used in actuators. An example is pneumatic rack and pinion actuators that can be used to control valves in pipeline transport. The actuators in the picture on the ri ght are used to control the valves of large water pipeline. In the top actuator, a gray control signal line can be seen connecting to a solenoid valve (the small black box attached to the back of the top actuator), which is used as the pilot for the actuator. The solenoid valve controls the air pressure coming from the input air line (the small green tube). The output air from the solenoid valve is fed to the chamber in the mi ddle of the actuator, increasing the pressure. The pressure in the actuator's chamber pushes the pistons away. While the pistons are moving apart from each other, the attached racks are also moved along the pistons in the opposite directions of the two racks. The two racks are meshed to a pinion at the direct opposite teeth of the pinion. When the two racks move, the pinion is turned, causing the attached main valve of the water pipe to turn.

Belt (mechanical) From Wikipedia, the free encyclopedia

 A pair of vee-belts

flat belt

Flat belt drive in the machine shop at the Hagley Museum

 A belt is a loop of flexible material used to mechanically link two or more rotating shafts, most often parallel. Belts may be used as a source of motion, to transmit power efficiently, or to track relative movement. Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need not be parallel. In a two pulley system, the belt can either drive the pulleys normally in one direction (the same if on parallel shafts), or the belt may be crossed, so that the direction of the driven shaft is reversed (the opposite direction to the driver if on parallel shafts). As a source of motion, a conveyor belt is one application where the belt is adapted to continuously carry a load between two points. Flat belts were widely used in the 19th and early 20th centuries in line shafting to transmit power in factories.[2] They were also used in countless farming, mining, and loggingapplications, such as bucksaws, sawmills, threshers, silo blowers, conveyors for filling corn cribs or haylofts, balers, water pumps (for wells, mines, or swampy farm fields), andelectrical generators. Flat belts are still used today, although not nearly as much as in the line shaft era. The flat belt is a simple system of power transmission that was well suited for its day. It can deliver high power at high speeds (500 hp at 10,000 ft/min or 373 kW at 51 m/s), in cases

of wide belts and large pulleys. But these wide-belt-large-pulley drives are bulky, consuming lots of space while requiring high tension leading to high loads, and are poorly suited to close-centers applications, so V-belts have mainly replaced flat-belts for short-distance power transmission; and longer -distance power transmission is typically no longer done with belts at all. For example, factory machines now tend to have individual electric motors. Because flat belts tend to climb towards the higher side of the p ulley, pulleys were made with a slightly convex or "crowned" surface (rather than flat) to allow the belt to self-center as it runs. Flat belts also tend to slip on the pulley face when heavy loads are applied, and many p roprietary belt dressings were available that could be applied to the belts to increase friction, and so power transmission. Flat belts were traditionally made of leather or fabric. Today most are made of rubber or polymers. Grip of leather belts is often better if they are assembled with the hair side (outer side) of the leather against the pulley, although some belts are instead given a half-twist before joining the ends (forming a Möbius strip), so that wear can be evenly distributed on both sides of the belt. Belts ends are joined by lacing the ends together with leather thonging (the oldest of the methods) ,[3][4] steel comb fasteners and/or lacing,[5] or by gluing or welding (in the case of polyurethane or polyester). Flat belts were traditionally jointed, and still usually are, but they can also be made with endless construction.

Fixture (tool) From Wikipedia, the free encyclopedia

 A common type of fixture, used inmaterials tensile testing

 A fixture is a work-holding or support device used in the manufacturing industry.[1][2] Fixtures are used to securely locate (position in a specific location or orientation) and support the work, ensuring that all parts produced using the fixture will maintain conformity and interchangeability. Using a fixture improves the economy of production by allowing smooth operation and quick transition from part to part, reducing the requirement for skilled labor by simplifying how workpieces are mounted, and increasing conformity across a production run.[2]  A fixture differs from a jig in that when a fixture is used, the tool must move relative to the workpiece; a jig moves the piece while the tool remains stationary.[3]

Purpose[edit]  A fixture's primary purpose is to create a secure mounting point for a workpiece, allowing for support during operation and increased accuracy, precision, reliability, and interchangeability in the finished parts. It also serves to reduce working ti me by allowing quick set-up, and by smoothing the transition from part to part.[3] It frequently reduces the complexity of a process, allowing for unskilled workers to perform it and effectively transferring the skill of the tool maker to the unskilled worker .[2] Fixtures also allow for a higher degree of operator safety by reducing the concentration and effort required to hold a piece steady . [3] Economically speaking the most valuable function of a fixture is to reduce labor costs. Without a fixture, operating a machine or process may require two or more operators; using a fixture can eliminate one of the operators by securing the workpiece. [4]

Design[edit]

These modular fixture components may be built into various arrangements to accommodate different workpieces

Fixtures must always be designed with economics in mind; the purpose of these devices is to reduce costs, and so they must be designed in such a way that the cost reduction outweighs the cost of implementing the fixture. It is usually better, from an economic standpoint, for a fixture to result in a small cost reduction for a process in constant use, than for a large cost r eduction for a process used only occasionally.[4]

 A common bench vise; the left jaw is the immovable surface, and the right jaw is the movable clamp

Most fixtures have a solid component, affixed to the floor or to the body of the machine and considered immovable relative to the motion of the machining bit, and one or more movable components known as clamps. These clamps (which may be operated by many different mechanical means) allow workpieces to be easily placed in the machine or removed, and yet stay secure during operation. Many are also adjustable, allowing for workpieces of different sizes to be used for different ope rations. Fixtures must be designed such that the pressure or motion of the machining operation (usually known as the feed) is directed primarily against the solid component of the fixture. This reduces the likelihood that the fixture will fail, interrupting the operation and potentially causing damage to infrastructure, components, or operators.[5] Fixtures may also be designed for very gen eral or simple uses. These multi-use fixtures tend to be very simple themselves, often relying on the precision and ingenuity of the operator, as well as surfaces and components already present in the workshop, to provide the same benefits of a specially-designed fixture. Examples include workshop vises, adjustable clamps, and improvised devices such as weights and furniture. Each component of a fixture is designed for one of two purposes: location or support.

 A drill is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for boring holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of the drill and rotated while pressed against the target material. The tip, and sometimes edges, of the cutting tool does the work of cutting into the target material. This may be slicing off thin shavings (twist drills or auger bits), grinding off small particles (oil drilling), crushing and removing pieces of the workpiece (SDS masonry drill), countersinking, counterboring, or other operations. Drills are commonly used in woodworking, metalworking, construction and do-it-yourself projects. Specially designed drills are also used in medicine, space missions and other applications. Drills are available with a wide variety of p erformance characteristics, such as power and capacity. Bow drill (strap-drills) are the first machine drills, as they convert a back-and forth motion to a rotary motion, and they can be traced back to around 10,000 years ago. It was discovered that tying a cord around a stick, and then attaching the ends of the string to the ends of a stick(a bow), allowed a user to drill quicker and more efficiently. Mainly used to create fire, bow-drills were also used in ancient woodwork, stonework and dentistry. Archeologist discovered a Neolithic grave yard in Mehrgrath, Pakistan dating from the time of the Harappans, around 7,500-9,000 years ago, containing 9 adult bodies with a total of 11 teeth that had been drilled.[4] There are hieroglyphs depicting Egyptian carpenters and bead makers in a tomb at Thebes using bow-drills. The earliest evidence of these tools being used in Egypt dates back to around 2500 BCE.[5] The usage of bow-drills was widely spread through Europe, Africa, Asia and North America, during ancient times and is still used today. Over the years many slight variations of bow and strap drills have developed for the various uses of either boring through materials or lighting fires. The core drill was developed in ancient Egypt by 3000 BC.[6] The pump drill was invented during Roman times, it consists of a vertical spindle aligned by a piece of horizontal wood and a flywheel to maintain accuracy and momentum.[7] The hollow-borer tip, first used around the 13th century, consisted of a stick with a tubular shaped piece of metal on the end, such as copper . This allowed a hole to be drilled while only actually grinding the outer section of it. This completely separates the inner stone or wood from the rest, allowing the drill to pulverize less material to create a similar sized hole.[8] While the pump-drill and the bow-drill were used in Western Civilization to bore smaller holes for a larger part of human history, the Auger was used to drill larger holes starting sometime between Roman and Medieval ages. [9] The auger allowed for more torque for larger holes. It is uncertain when the Brace and Bit was invented however the earliest picture found so far dates from the 15th century.[9] It is a type of hand crank drill that consists of two parts as seen in the picture. The brace, on the upper half, where the user holds and turns it and on the lower part is the bit. The bit is interchangeable as bits wear down. The auger u ses a rotating helical screw similar to the Archimedean screw shaped bit that is common today. The gimlet is also worth mentioning as it is scaled down version of an auger. In the East, churn drills were invented as early as 221 BC during the Chinese Qin Dynasty,[10] capable of reaching a depth of 1500 m.[6] Churn drills in ancient China were built of wood and labor-intensive, but were able to go through solid rock.[11] The churn drill appears in Europe during the 12th century. [6] In 1835 Isaac Singer is reported to have built a steam powered churn drill based off the method the Chinese used.[12] Also worth briefly discussing are the early drill presses, they were machine tools that derived from bow-drills but were powered by windmills and water wheels. Drill presses consisted of the powered drills that could be raised or lowered into a material, allowing for less force by the user. The next great advancement in drilling technology, the electric motor , led to the invention of the electric drill. It is credited to Arthur James Arnot and William Blanch Brain of Melbourne, Australia who patented the electric drill in 1889.[13] In 1895, the first portable handheld drill was created by brothers, Wilhem & Carl Fein, from Stuttgart Germany. In 1917 the first trigger switch, pistol-grip portable drill was patented by Black & Decker .[14] This was the start of the modern drill era. Over the last century the electric drill has been created to the variety of types, and multiple sizes for a n assortment of specific uses.

Vibration Drilling[edit]

Titanium chips - conventional drilling vs vibration drilling

Vibration drilling of an aluminum-CFRP multi-material stack with MITIS technology

The first works on vibration drilling began in the 1950s (Pr. V.N. Poduraev, Moscow Bauman University). The main p rinciple consists in generating axial vibrations or oscillations in addition to the feed movement of the drill so that chips could be fractionated and easily removed from the cutting zone. One can find two main technologies of vibration drilling: self-maintained vibrations systems and forced vibrations systems. Most vibration drilling technologies are still at a research stage. It is the case of the self-maintained vibrations drilling: the eigen frequency of the tool is used in order to make it naturally vibrate while cutting; vibrations are self-maintained by a mass-spring system included in the tool holder .[6] Other works use a piezoelectric system to generate and control the vibrations. These systems allow high vibration frequencies (up to 2 kHz) for small magnitude (about a few micrometers); they particularly fit drilling of small holes. Finally vibrations can be generated by mechanical systems:[7] the frequency is given by the combination of the rotation speed and the number of oscillation per rotation (a few oscillations per rotation), the magnitude is about 0.1 mm. This last technology is a fully industrial one (e xample: SineHoling® technology of MITIS). Vibration drilling is a favoured solution in order to face issues like deep hole drilling, multi-material stacks drilling (aeronautics) or dry drilling (without lubrication). Generally it allows increasing the reliability and the control of the drilling operation.

Circle interpolating [edit]

The orbital drilling principle

Circle interpolating , also known as orbital drilling , is a process for creating holes using machine cutters. Orbital drilling is based on rotating a cutting tool around its own axis and simultaneously about a centre axis which is off-set from the axis of the cutting tool. The cutting tool can then be moved simultaneously in an axial direction to drill or machine a hole  – and/or combined with an arbitrary sidewards motion to machine an opening or cavity. By adjusting the offset, a cutting tool of a specific diameter can be used to drill holes of different diameters as illustrated. This implies that the cutting tool inventory can be substantially reduced. The term orbital drilling comes from that the cutting tool “orbits” around the hole center. The m echanically forced, dynamic offset in orbital drilling has several advantages compared to conventional drilling that drastically increases the hole precision. The lower thrust force results in a burr-less hole when drilling in metals. When drilling incomposite materials the problem with delamination is eliminated.[8]

Material[edit]

Drilling in metal [edit]

High speed steel twist bit drilling into aluminium with methylated spirits lubricant

Under normal usage, swarf is carried up and away from the tip of the drill bit by the fluting of the drill bit. The cutting edges produce more chips which continue the movement of the chips outwards from the hole. This is successful until the chips pack too tightly, either because of deeper than normal holes or insufficient backing off  (removing the drill slightly or totally from the hole while drilling). Cutting fluid is sometimes used to ease this problem and to prolong the tool's life by cooling and lubricating the tip and chip flow. Coolant may be introduced via holes through the drill shank, which is common when using a gun drill. When cutting aluminum in particular, cutting fluid helps ensure a smooth and accurate hole while preventing the metal from grabbing the drill bit in the process of drilling the hole. When cutting brass, another soft metal that can grab the drill bit and cau ses "chatter" the cutting edges of the drill bit, which normally form an acute angle, a face of approx. 1-2 millimeters can be ground on

the cutting edge to create an obtuse angle of 91 to 93 degrees. This prevents "chatter" where the drill tears rather than cuts the metal. However, the drill is pushing the metal away. This creates high friction and very hot swarf. For heavy feeds and comparatively deep holes oil-hole drills can be used, with a lubricant pumped to the drill head through a small hole in the bit and flowing out along the fluting. A conventional drill press arrangement can be used in oil-hole drilling, but it is more commonly seen in automatic drilling machinery in which it is the workpiece that rotates rather than the drill bit. In computer numerical control (CNC) machine tools a process called peck drilling , or interrupted cut drilling , is used to keep swarf from detrimentally building up when drilling deep holes (approximately when the depth of the hole is three times greater than the drill diameter). Peck drilling involves plunging the drill part way through the workpiece, no more than five times the diameter of the drill, and then retracting it to the surface. This is repeated until the hole is finished. A modified form of this process, called high speed peck drilling  or chip breaking , only retracts the drill slightly. This process is faster, but is only used in moderately long holes otherwise it will overheat the drill bit. It is also used when drilling stringy material to break the chips .[9][10][11]

CONTENTS Candidate’s Declaration

i

Acknowledgement

ii

Abstract

iii

Contents

iv-v

List of Figure

vi

Chapter 1 Electromagnetic Crane

1-6



Introduction

1-3



History

3-4



What is crane

4-5



Applications

5



Working

5-6



Part List

6

Chapter 2:

Switch

7-9



Introduction



Circuit Theory



Power Switching

8



Inductive Loads

9

Chapter 3: Pulley

7 8

10-12



Introduction

10



Working

11-12

Chapter 4: Electrical

13-19



Introduction

13



History

13-14



Categorization of electric motors

14



DC Motor

14-15



Types of DC Motor

15-17



Universal Motor

17-18



Torque Motor

Chapter 5: Coil

18-19

20-21



Introduction

20



Analysis

21

Chapter 6: Caster Wheel 

Introduction

22-24 22