FIELD OF THE INVENTION
[001] The present invention relates generally to Free Play in cable type clutch release system. More particularly, the present invention relates to Spring Loader Assembly and method of use thereof to maintain Free-Play in Cable type Clutch Release System. 5
BACKGROUND OF THE INVENTION
[002] Clutch, in general, refers to a device to connect driving and driven (coaxial) shafts of a machine, where a driven shaft can be disconnected (almost instantaneously) from the drive shaft as desired by the operator or user. 10
[003] In a cable type manual transmission clutch is engaged and disengaged mechanically by a clutch cable (15) which is connected to clutch pedal (10) at one end and clutch release arm (20) onto another end. Clutch release arm (20) is connected to clutch release bearing 15 (25) by means of clutch release shaft (30) as shown in fig 2.
[004] When clutch pedal (10) is pressed, said clutch cable (15) pulls the clutch release arm (20) thereby constraining the motion of said clutch release arm (20). The constrained motion of said clutch release 20 arm (20) and said clutch release shaft (30) actuates said clutch release bearing (25) to disengage the clutch.
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[005] When said clutch pedal (10) is released or when the clutch is engaged, said clutch cable (15) releases the pulling force on said cutch release arm (20).
[006] When said clutch pedal (not shown) is not pressed, there is 5 some clearance between clutch cover (40) fingers and said clutch release bearing (25) to avoid clutch riding. This clearance is called ‘Gap for Free-Play’ (45) as shown in Fig.4.
[007] Fig. 3 discloses the Free Play (50) in the said clutch pedal (10) 10 because of clearance between said clutch cover (40) fingers and said clutch release bearing (25), also known as “gap for free play” (45).
[008] It has been the practice to predict wear of the friction lining material as a function of diminishing free play of said clutch pedal (10). As the original free play diminishes after a predetermined 15 amount, it is assumed there is a need to re-adjust the clutch linkage system to reestablish the original free play of said clutch pedal (10). The clutch release arm and clutch release shaft assembly is then adjusted by tightening or loosening of a free play adjustment nut (35) to re-establish a predetermined amount of free play in said clutch 20 pedal (10). This manual adjustment re-established the geometry of the clutch linkage system.
[009] A serious disadvantage of this particular practice of adjusting the clutch is that the operator of the clutch is frequently ignorant of the 25 fact that lack of sufficient free play in said clutch pedal (10) is an
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indication that the clutch lining has worn a sufficient amount to require adjustment of the clutch. This particular type of operator would normally re-adjust the clutch only after experiencing severe clutch slippage. Generation of heat as a result of severe clutch slippage oftentimes results in considerable permanent damage to certain of the 5 clutch elements.
[0010] Further, since the actual gap for free play (45) is not visible to the operator, it leads to subjectivity and requires more skill on the part of the operator for free play adjustment. 10
[0011] US3286803A discloses Adjustment mechanism for clutch linkage. The mechanism is particularly suitable for use in a system wherein a linkage mechanism is employed to actuate a device and wherein it becomes desirable to readjust the linkage mechanism with 15 respect to the device being actuated to compensate for a condition such as, for example, wear. In other words, wear of the device being actuated and/ or wear of the linkage members per se may result in a change in geometry of the system and dictate a need to readjust the linkage members to re-establish the original relative position of certain 20 of the linkage members.
[0012] A serious disadvantage of particular practice of adjusting the clutch is that the operator of the clutch is frequently ignorant of the fact that lack of sufficient free play in said clutch pedal (10) is an 25 indication that the clutch lining has worn a sufficient amount to
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require adjustment of the clutch. This particular type of operator would normally re-adjust the clutch only after experiencing severe clutch slippage. Generation of heat as a result of severe clutch slippage oftentimes results in considerable permanent damage to certain of the clutch elements. 5
[0013] Further, since the actual gap for free play (45) is not visible to the operator, it leads to subjectivity and requires more skill on the part of the operator for free play adjustment.
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[0014] WO0066904A1 discloses a device for automatic take up of play in a clutch control circuit, wherein a mechanical transmission device comprising a spring is compressed between a first support component fixed at the proper position on a pull wire connected to the coupling control unit and a second support component pressed against the end 15 of a clutch release fork, via a mass of shock absorbing material. The wear of the linings causes the stop element to slip and the spring to be compressed against the first support component. When the clutch is released by pulling the wire, the spring is entirely compressed, and the first support component appropriately moves the fork by being 20 supported on the second support component.
[0015] The above invention relates to a wear adjustment mechanism of a friction clutch, whose drawback is that the dead travel reduces to zero when the clutch is worn out. 25
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[0016] Hence there is a need for a solution through which the free-play of the clutch can be re-adjusted easily and more efficiently and that the dead travel does not reduce to zero when clutch is worn out.
OBJECTS OF THE INVENTION
[0017] It is therefore an object of the present invention to manufacture 5 a spring loader assembly for free-play mechanism.
[0018] Another object of the present invention to manufacture a spring loader assembly to improve idle vibrations at clutch pedal.
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[0019] Yet another object of the present invention to manufacture a spring loader assembly for eliminating rubbing noise of clutch release bearing due to drag.
[0020] A still further object of the present invention to manufacture a 15 spring loader assembly for ease of free-play adjustment of clutch pedal.
SUMMARY OF THE INVENTION
[0021] In manual clutch release system, a clearance is provided between clutch release bearing (25) and clutch diaphragm fingers (not 20 shown) to maintain free- play at clutch pedal. A spring loader according to the present invention consists of a spring (15) which is assembled inside the pair of spring housing (110A & 110B). The whole unit is snap locked, with the help of a snap lock (100) to preload said spring (115) and assembled onto said clutch release arm 25
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(20). Said reloaded spring (115) applies a force on said clutch release arm (20) to push said clutch release bearing (25) onto the clutch cover diaphragm fingers. The gap between said housings (110A and 110B) ensures the required free play on clutch pedal.
BRIEF DESCRIPTIONS OF THE ACCOMPANYING 5 DRAWINGS
[0022] The above brief description, as well as further objects, features and advantages, of the present invention can be fully appreciated by reference to the following detailed description. These features of the present invention will become more apparent upon reference to the 10 drawings, wherein:
[0023] Fig. 1: Existing assembly of clutch release system
[0024] Fig. 2: A-A section of Fig. 1
[0025] Fig. 3: Free Play in a Clutch 15
[0026] Fig. 4: Existing Free play mechanism
[0027] Fig. 5: Spring loader assembly according to the present invention in assembled condition
[0028] Fig. 6: Spring loader assembly according to the present invention in unassembled condition 20
[0029] Fig. 7: Free play mechanism according to the present invention
DETAIL DESCRIPTION OF THE INVENTION
[0030] The present invention will be described in detail below with reference to an embodiment as shown in the drawing.
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[0031] Referring to Fig. 5, a spring loader assembly (200) in assembled condition is disclosed. Said spring loader assembly (200) comprises of a spring (115) compressed between a pair of hollow cylinders (110A & 110B). Said spring (115) is compressed and said hollow cylinders (110A & 110B) are snap locked with the help of a snap lock (100) to 5 make it a complete assembly which is to be mounted on said clutch release arm (20).
[0032] Referring to Fig. 6, said spring loader assembly (200) is disclosed in an unassembled (unlocked) condition wherein said spring 10 (115) is uncompressed between said pair of hollow cylinders (110A & 110B).
[0033] Said housing (110A & 110B) is made from hard synthetic polymers such as Polyvinylchloride (PVC), Polypropylene (PP), 15 Polytetrafluoroethylene (PTFE), etc.
[0034] Said spring (115) can be selected from Compression Spring, Torsion Spring or Leaf type Flat Spring.
[0035] Said spring loader assembly (200), in assembled condition, is 20 mounted on said clutch release arm (20), with the help of openings (105) on the side of hollow cylinders (110A & 110B). Said clutch cable (15) passes through said openings (105) and spring (115). When said spring loader assembly (200) is in an assembled condition and mounted on said clutch release arm (20), said spring (115) applies an 25 equal and opposite force on both said housings (110A and 110B). The
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housing (110B), which is in contact with said clutch release arm (20) pushes (60) said clutch release arm (20) in forward direction which in turns pushes said clutch release bearing (25) to preload the clutch fingers. The other housing (110A) pulls (70) said clutch cable (15) in opposite direction to keep it in tension against said clutch pedal (10) as 5 shown in fig 7.
[0036] Gap for Free-Play (45) according to the present invention comes from the clearance between said pair of housing (110A & 110B) while in existing system free play is because of the clearance between clutch 10 release bearing (25) and clutch diaphragm fingers. For initial 10 to 15mm travel of clutch pedal (10), said housing (110A & 110B) moves towards each other and clearance between them reduces to zero and provides the desired free play. When said clutch pedal (10) is pressed further said spring loader assembly (200) becomes a solid link and 15 transfers whole pedal force to said clutch release arm (20) to actuate clutch diaphragm spring.
[0037] Said snap lock (100) prevents said spring (115) and said clutch cable (15) from twisting and twirling hence reducing the chances of 20 them being damaged. Further, said since spring loader assembly (200) is visible and easily within the reach of the mechanic, clutch pedal free play adjustment becomes very easy.
[0038] The invention has below distinct advantages / changes with 25 respect to current system.
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1. Pedal reserve increases giving more freedom for pedal travel reduction
2. Better feeling during pedal return in free play zone
3. Eliminates rubbing noise of clutch release bearing due to drag.
4. Improve idle vibrations at clutch pedal which transfer through 5 inner cable.
[0039] The present invention also obviates the need of following components from the release system, and in turn making the release system cost effective and more efficient:
1. Pin clutch cable joint 10
2. Spring clutch release shaft
3. Spring clutch pedal return
4. Cap clutch cable joint lock

WE CLAIM:
1. A spring loader assembly (200), comprising:
A pair of hollow cylindrical housing (110A & 110B);
A spring (115) compressed between said pair of hollow cylindrical housing (110A & 110B); 5
Said pair of hollow cylindrical housing (110A & 110B) connected to each other with a snap lock (100).
2. The spring loader assembly (200) as claimed in claim 1, wherein said each housing (110A & 110B) has an opening 10 (105).
3. The spring loader assembly (200) as claimed in claim 1, wherein said pair of hollow cylindrical housing (110A & 110B) is made from hard synthetic polymers such as Polyvinylchloride 15 (PVC), Polypropylene (PP), Polytetrafluoroethylene (PTFE).
4. The spring loader assembly (200) as claimed in claim 1, wherein said spring (115) is selected from Compression Spring, Torsion Spring or Leaf type Flat Spring. 20
5. A spring loaded free play mechanism wherein:
Said spring loader assembly (200), in assembled condition, is mounted on said clutch release arm (20) wherein said spring 25 loader assembly (200) is mounted with the help of openings (105) on each side of said hollow cylinders (110A & 110B);
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Said clutch cable (15) is passed through said openings (105) and said spring (115);
an equal and opposite force is applied on both said housings (110A and 110B), by said spring (115);
said housing (110B), which is in contact with said clutch release 5 arm (20), exerts a pushing force (60) on said clutch release arm (20) in forward direction;
said pushing force (60) pushes said clutch release bearing (25) to preload the clutch fingers; and
The other housing (110A) exerts a pulling force (70) on said 10 clutch cable (15) in opposite direction to keep it in tension against said clutch pedal (10).