FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"STACK UP TROLLEY FOR COLLECTING BLANK SCRAPS"
MAHINDRA & MAHINDRA LIMITED
A COMPANY REGISTERED UNDER THE
PROVISIONS OF COMPANIES ACT, 1956
HAVING ADDRESS AT R & D CENTER,
AUTOMOTIVE SECTOR,
89, M.I.D.C., SATPUR,
NASHIK - 422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION:-
The present invention is related to the improved process of die shop in the manufacturing operations. More particularly the present invention is related to the stack up trolley system for collecting blank scarp in the manufacturing process.
DESCRIPTION OF THE PRESENT INVENTION:-
The purpose of the present invention is (i) Scrap flow rate is 21 Nos per minute, (ii) Scrap size (771X587) and weight (2 kg.), and (iii) Production should not stop for the reason of trolley load/unload.
The invention of the present invention comprises of two trolleys one is fixed trolley and other is moving trolley, at the same time there should be two stations in trolley for collecting scraps first with fixed trolley & second with moving trolley, First station (Fixed trolley) for initial collection of 40 to 45 scraps that requires approx 2 minutes which is sufficient for move away loaded trolley & reloading another empty trolley. Second station (moving trolley ) where scraps from first station gets collected.
Four Counter weights ( Total wt. 80Kg) provided with fixed trolley , Initial batch of scraps get collected in fixed trolley the moment scrap wt (40 scrap wt=80 Kg) exceeds counter wt (80 Kg.) Counter blocks swing down & batch of 40 scraps fall down in moving trolley, Accordingly cycle rotates & approx 360 scraps collected in moving trolley .Once 360scraps collected in moving trolley unload it & load another empty trolley for collecting first batch of 40 scraps.
Part will be guided until the belt conveyor. It is then collected in trays. Once the tray is full with the part. It will get collected in trolley. Springs are adjusted in such a way that it will hold the tray in normal position. Once the tray is full the springs will get compressed which will allow the tray to move downwards in horizontal/stacked condition.

For designing minimum Conveyor angle to initiate scrap sliding following inputs considered.
■ Coefficient of Friction for Roller contact Bearing - 0.2 u
■ The relation between coefficient of friction & Angle of friction 9 i.e. minimum angle before which one of the part begin sliding, Which is given
by,
9 = u
9 = tan "1* u , By putting values & calculating
9= 11.3°
Automation has been done on trolley for ensuring safe working. Following things
are ensured in Automation,
(i) Signal for Moving Trolley presence : In case moving trolley not present below fixed trolley all scrap cut outs will fall on ground, to avoid this one proxy sensor (Specification-M30x1.5-IFW,Make-BALLUF) is installed on Fixed trolley which will sense presence of Moving trolley , If moving trolley is not at required place it will give signal & emergency alarm will blow.
(ii) Signal for Loaded Moving Trolley : In case moving trolley get completely loaded with material, there should be signal to indicate this other wise there would be malfunction. To avoid this we have installed limit switches (specification-WLCA2 ,Make-SMC) nearby counter weight of trolley. For every swing of counter weight (i.e. one batch 40 scraps falling in moving trolley) limit switch will get activated & give a signal to timer, For every 9 signals timer give signal to emergency lamp to indicate that we need to remove loaded trolley. This way we can ensure that moving trolley need to replace with empty trolley once it is loaded with approx. 360 scraps.
STATEMENT OF THE INVENTION:-
Stack up trolley for collecting blank scraps comprising of a fixed stack up trolley mounted in front of sliding gate, said fixed stack up trolley having a roller strip, conveyor and a stationery blank collection area at the top side to collect the scarp flowing from the blanking die; a moving trolley is provided below the said fixed

stack up trolley such a that the fixed trolley gets arrested with the help of tower bolts to collect the blank scraps in stack up manner; counterweight blocks are pivotally mounted below the said fixed stack up trolley in such a manner that once the weight of scrap exceeds the weight of counter weight blocks, the said counterweight blocks unswing so that the collected scrap falls down in a moving trolley which shall be taken to the required station for collection.
BRIEF DESCRIPTION OF THE FIGURES:-
Figure 1 is schematic representation of press layout alongwith the stack up trolley for collecting blank scraps as per the present invention.
Figure 2 shows the schematic representation of stack up trolley for collecting blank scraps as per the present invention and part operation flow.
Figure 3 shows the schematic representation of fixed stack up trolley as per the present invention.
Figure 4 shows the schematic representation of working of stack up trolley alongwith the counter blocks as per the present invention.
Figure 5 shows the schematic representation working of stack up trolley.
Figure 6 shows the schematic representation of moving trolley.
Figure 7 shows the schematic representation of door inner part operation flow.
Figure 8 shows the schematic representation of stack up trolley for door inner scrap (Round in Geometry)

DETAILED DESCRIPTION OF THE INVENTION:-
Present invention will now be described with reference to the drawings of the accompanying specification and essential components/parts are shown by suitable numerals to describe the invention.
Drawings of the accompanying specification are only for the purpose of describing the invention and shall not be construed as a limitation of the invention.
Various other embodiments are possible without departing from the scope of the present invention.
Figures 1 & 2 shows schematic representation of auto press line blanking station & part operation flow respectively. Blanks are required for different draw operation i.e. Body Side Outer (BSO), Door Outer, etc
Following are the components shown in the layout.
This is BSO blank die which is installed on auto press. In blanking die required shapes are cut (Blank layout_5) from stagnated sheet metal roller material. Scraps used to slide out from blanking dies. Chutes are provided on die for directing scraps. Blank scrap flow rate is approximately 20 to 21 per minute and blank scrap size is approximately 770 X 580. Blank scrap weight is approximately 2Kg. Main requirement is to collect blank scrap continuously i.e. without stopping press line. As shown in fig_2 required blank layout (5) produced from blanking die & from this said blank one Body side outer part (6) is produced.
As shown in figure sliding door is the part of Press line station. Sliding door slides up and down and main purpose of sliding door is for safety. There is a pit in between blanking Die and sliding door, presently there is no provision for collecting blank scraps. Through pit it flows towards scrap yard. On sliding door there is small rectangular opening through which we can collect scraps.

As shown in figure stack up trolley is special purpose machine (SPM) designed to collect blanking scraps from auto press, without stopping production. Scrap trolley mounted in front of sliding gate for collecting scraps flowing through door opening.
Figure 3 shows schematic representation of fixed stack up trolley mounted in
front of sliding gate. Scrap is collected in to trolley which is flowing from blanking
die.
Following components are shown in layout.
• Roller strip (7) - Roller strip is a Standard roller part & make is SANKYO. Catalogue part No. is SCB_36P_50_1000.Where SCB is part description, 36P is pitch between two rollers, 50 is width of roller strip & 1000 is length of roller strip. This roller strip is mounted on Conveyor (8) with the help of nut & bolts.
• Conveyor (8) - Conveyor is fabricated structure made from 25*25 'L' channel. Two strips are pivot joined to conveyor, lower end of strips rested on fixed trolley (10). Upper part of conveyor of pivot joined with fixed trolley (10).
• Design of Sliding angle of conveyor.
Coefficient of Friction for Roller contact Bearing - 0.2 u

■ The relation between coefficient of friction & Angle of friction θ i.e. minimum angle before which one of the part begin sliding, Which is given by,
tanθ = μ
θ = tan -1* μ , By putting values & calculating
θ= 11.3°

• Counter Weight (9) - Counter weights are solid block pivot joined to fixed trolley (10). Pivot joinery done by pivot pins with collar at one end & quarter pin at other end. Weight of counter block calculated from no. of scraps we need to collect in fixed trolley. As shown in figure each side counter weights are joined with each other with the help of connecting plate. Blocks joined to ensure there should be simultaneous swing of each side blocks.
• Counter Weight Block Design - For designing counter block weight following inputs are considered.
Each Scrap weight = 2 Kg.
No. of scraps decided to collect in one batch = 40 Nos.
• Equation for Counter Block Weight
W = (No of scraps in each batch) X (Wt. of each scrap)
= 40X2
= 80 Kg.
Where W is Total weight of counter blocks.
If we plan 4 Counter Blocks then Each counter Block Wt = 20 Kg. From above equation we can derive a generalized equation for any kind of blank scrap.
i.e. W = (No. of scraps in each batch (40)) X (Wt. of each scrap
(9))
W = 40*g.
• Equation For time required to collect one batch of scraps (40 No.
scraps)
80 = (No of scraps floe per min.) X (time 't') X (Wt. of each scrap) 80 = 20 X t X 2 't'= 2 Minuets.
• Fixed Trolley (10) - Fixed trolley is fabricated structure made up of 25x25
Sq. pipe with 2.5 mm thickness. Pipe pieces welded with each other to
make a required structure. In fixed trolley there is stationary blank
collection area at top side where we can collect up to 40 blank scraps.

Four tower bolts fixed at lower end of trolley for fixing trolley on ground at required position.
• Safety Mat (11) - Safety mat located at three sides of fixed trolley. Purpose of safety mat is to avoid damage of flowing scraps. When speedy flowing scrap enter in fixed trolley first it will rest / guide with the help of safety mat.
• Limit Switch (12) - Limit switch is mounted on fixed trolley to give signal for loaded trolley. In case moving trolley get completely loaded with material, there should be signal to indicate this otherwise there would be malfunction. To avoid this we have installed limit switches (specification-WLCA2 ,Make-SMC) nearby counter weight of trolley. For every swing of counter weight (i.e. one batch 40 scraps falling in moving trolley) limit switch will get activated & give a signal to timer, For every 9 signals timer give signal to emergency lamp to indicate that we need to remove loaded trolley. This way we can ensure that moving trolley need to replace with empty trolley once it is loaded with approx. 360 scraps.
• Proxy sensor (13) - Proxy sensor installed on fixed trolley to sense the presence of Moving Trolley. In case moving trolley not present below fixed trolley all scrap cut outs will fall on ground, to avoid this one proxy sensor (Specification-M30x1.5-IFW,Make-BALLUF) is installed on Fixed trolley (10) which will sense presence of Moving trolley , If moving trolley is not at required place it will give signal & emergency alarm (14) will blow.
• Emergency Alarm (14) - Emergency alarm installed on fixed trolley. In case of any malfunction emergency alarm will get signal from Limit switch (12) or Proxy sensor (13) & it will blow.
• Tower Bolt (15) - Tower bolts are fitted at lower end of fixed trolley. Function of tower bolt is to fix the trolley on ground at required location.
Figure 4 shows fixed trolley mounted in front of press. Fixed trolley position arrested with the help of tower bolts. Empty moving trolley entered in between fixed trolley. As shown in figure, scraps (16) collected in fixed trolley. Total weight of four counter blocks is approximately 80Kg (09). As explained earlier we have designed counter blocks to collect 40 scraps. Till 40 scraps counter block will not

swing down. Once scrap weight exceed counter weight, it will start swing. As shown in figure empty trolley loaded before falling of blank scraps.
Figure 5 shows working of stack up trolley as explained in earlier scrap (16) is approximately 80 Kg collected in fixed trolley. Once Scrap weight exceeds counter weight (09) counter blocks will get unswing & whole batch of scraps will fall down in moving trolley. In similar way once the appropriate scraps get collected in a moving trolley signal will be given to alarm & it will blow. Operator will unload loaded trolley & will replace empty trolley.
Figure 6 shows schematic representation of moving trolley-
• Moving Trolley (17) - Moving trolley is fabricated structure made up of 25x25 Sq. pipe with 2.5 mm thickness. Pipe pieces welded with each other to make a required structure. In moving trolley blank scraps get collected in stack up manner.
• Safety mat for moving Trolley (18) - Mat is provided at bottom side of moving trolley. Mat is provided to avoid scrap damage. Mat material is rubber or Nylon.
• Wheels (19) - Wheels provided at bottom of moving trolley. Purpose of whales is to move trolley from one station to other station. Wheels are standard and selected based on weight carrying capacity. Four wheels required for each moving trolley.
• Lifting Bracket (20) - Lifting bracket is mounted on moving trolley, On lifting bracket safety mat is placed. Lifting bracket is designed in such a way that we can lift it with fork lift also. This is fabricated structure with 40X40 pipe structure having thickness of 2.5 mm.
Figure 7 shows schematic representation of door inner part operation flow
Figure 8 shows schematic representation of stack up trolley for door inner scrap (Round in Geometry)

As shown in figure 8, same concept of stack up trolley been used for different geometry pars also. For utilizing same concept we need to change following things in existing trolley.
• Depending on weight of scrap we need to redesign counter block weight.
• As per generalized counter block weight equation (W = 40*g , g= Wt. of each scrap) we need to design counter block wt.
• Conveyor size we need to change as per part profile.
• Overall fixed trolley (10) & moving trolley (17) size we need to recheck based on size / profile of blank scrap.
Figure (7) shows schematic representation of Door inner Part operation flow, Blank layout is different & geometry of scrap which need to collect also different. Figure (8) shows actual scrap collecting trolley designed for collecting round shaped scrap.

WE CLAIM:-
1. Stack up trolley for collecting blank scraps comprising of a fixed stack up trolley mounted in front of sliding gate, said fixed stack up trolley having a roller strip, conveyor and a stationery blank collection area at the top side to collect the scarp flowing from the blanking die; a moving trolley is provided below the said fixed stack up trolley such a that the fixed trolley gets arrested with the help of tower bolts to collect the blank scraps in stack up manner; counterweight blocks are pivotally mounted below the said fixed stack up trolley in such a manner that once the weight of scrap exceeds the weight of counter weight blocks, the said counterweight blocks unswing so that the collected scrap falls down in a moving trolley which shall be taken to the required station for collection.
2. Stack up trolley as claimed in claim 1 wherein, the said counterweight blocks are solid blocks pivot joint to fix trolley having pivot pins with collar at one end and quarter pin at other end.
3. Stack up trolley as claimed in claims 1 and 2 wherein, sliding angle of conveyor is minimum angle with which one of the scraps begin sliding and calculated by the formula
tanθ = μ
θ = tan -1* μ, By putting values & calculating
θ= 11.3°
4. Stack up trolley as claimed in claim 1 wherein, a limit switch and/or proxy sensor are mounted on a fixed trolley to give signal for the loaded trolley for avoiding malfunctioning; the said limit switch and/or proxy sensor shall get activated for every swing of counterweight.
5. Stack up trolley as claimed in claim 1 wherein, an emergency alarm is installed on a fixed trolley to receive signal from limit switch or proxy sensor in case of malfunctioning.

6. Stack up trolley as claimed in claim 1 wherein, lifting bracket is mounted on the moving trolley alongwith safety mat for easier lifting of the collected scraps, wheels are provided at the bottom of the moving trolley to carry the loaded trolley from one station to another.