Title of Invention	AN AUTOMATIC LOCKING DEVICE FOR PREVENTING REVERSE POWER FLOW IN ROTARY POWER TRANSMISSION
Abstract	ABSTRACT AN AUTOMATIC LOCKING DEVICE FOR PREVENTING REVERSE POWER FLOW IN ROTARY POWER TRANSMISSION An automatic locking device for preventing reverse power flow in rotary power transmission comprising a power input shaft connected to a power output shaft; restraining means for preventing the output shaft from rotating when no torque is applied to the input shaft; an input member mounted on the input shaft and an output member mounted on the output shaft, said members, having coupling means for coupling them together when brought into contact with each other, on a torque being applied to the input shaft; connecting means connecting the input member to trie output member for enabling the output shaft to be initially driven by the input shaft until the input and output members are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is initially transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, the torque causes the output number to be drawn b^ the connecting means towards the input member so as to come into contact and couple therewith, to enable the output shaft to be driivn directly by the coupled input and output members. (Figure 1)

Title of Invention

AN AUTOMATIC LOCKING DEVICE FOR PREVENTING REVERSE POWER FLOW IN ROTARY POWER TRANSMISSION

Abstract

ABSTRACT AN AUTOMATIC LOCKING DEVICE FOR PREVENTING REVERSE POWER FLOW IN ROTARY POWER TRANSMISSION An automatic locking device for preventing reverse power flow in rotary power transmission comprising a power input shaft connected to a power output shaft; restraining means for preventing the output shaft from rotating when no torque is applied to the input shaft; an input member mounted on the input shaft and an output member mounted on the output shaft, said members, having coupling means for coupling them together when brought into contact with each other, on a torque being applied to the input shaft; connecting means connecting the input member to trie output member for enabling the output shaft to be initially driven by the input shaft until the input and output members are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is initially transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, the torque causes the output number to be drawn b^ the connecting means towards the input member so as to come into contact and couple therewith, to enable the output shaft to be driivn directly by the coupled input and output members. (Figure 1)

Full Text	Ibis invention relates to an automatic locking device for preventing reverse power flow in rotary power transmission. In. many applications a motor has to move a load and hold the load in. a fixed position either by employing a power brake or by controlling the motor current to prevent gravity or momentum from moving the Load. Solenoid operated brakes, worm gear reducers are solutions; however these mechanisms, consume power and are otherwise not efficient, so much so when a large power is involved this can cause substantial energy, lo%&. This invention therefore proposes an automatic locking device for preventing reverse power flow in rotary power transmission without incurring energj' loss either when the load is bemg driven by a motor or other prune mover or when the transmission shaft is tacked against YoUtisn. An automatic locking device for preventing reverse power flow in rotar}' power transmission according to this invention^ comprises a power input shaft connected to a power output shaft; restraining means SOT preventing the output shaft from rotating when no torque is applied to the input shaft; an input member mounted on the input shaft and an output member mounted on the output shaft, said members having coupling means for coupling them together when brought into contact with each other, on a torque being applied to the input shaft-, connecting means connecting the input member to the output member for enabling tne output shatt to be initially driven by the input shaft until the input and output members are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is imtiaUy transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, causes the output member to be drawn by the connecting means towards the input member so as to come in contact, and couple therewith, to enable the output shaft to be driven dh-ectiy by the coupled input and output members. This invention will now he described with reference to he accompanying drawings which illustrate, by way of example and not by way of limitation one of possible embodiments of the device proposed herein, Vie. 1 illustrating a general view in elevation of the embodiment Fi1£. 2 illustrating an exploded view of the embodiment Fig. 3 illustrating another general view of the embodiment tig. 4 illustrating a view in perspective of the embodiment from the output end; and I'ig. 5 illustrating a view in perspective of the embodiment from the input end. The embodiment has a power input shaft 1 supported hy two ball bearings 2 inside bearing bracket 3 fixed to the frame 4. The input member, which is the input dog 5, is linked to the output member, -which is the output dog 6, by connecting means which are two or more bail ended links 7, whose ends are anchored to the input dog and output dog respectively by split spherical concave sockets 8 bolted to the periphery of (he input dog and output dog. The said links 7 are thus free to swing in ail directions about their anchor points on the dogs. Resilient means, such as, the compressfon spring 9 disposed between the input and output members, exert a thrust tending to keep the said input dog and output dog apart, with the finks 7 in tension. The input dog 5 is fixed to the input shaft I by a key. The output shaft 1Q vs su\\vwvteA «n ball beatin&s I inswle the hiring bvacket 11 which is fixed to the frame 4. The said output shaft 10 has splines on it. The output dog 6 is assembled on to the output shaft 10 such that it is free to slide along the output shaft 10 but is constrained to rotate with it since the internal splines of the output dog 6 engage with the external splines of the output shaft 10. Fig. I illustrates the position when no torques is exerted on the input shaft 1. One side of the output dog 6 and an adjacent support, such as, the adjacent side of the hearing bracket 11, has jaws 13 which arc engaged together by the force exerted by the compression spring 9. It is not possible to rotate output shaft 10 because it would have to rotate output dog 6 too and that is not possible as the jaws 13 on the output dog 6 and stationary bracket 11 are meshed together. Figs. 3 and 4 show the angular displacements caused by (he links 7 on the input dog 5 pulling the output dog 6 towards the input dog 5, compressing the spring 9 resulting in the disengagement of jaws 13. A thrust bearing 1Z at the seating of the spring 9 on the input dog 5 ensures that the spring does not cause any torque due to winding or unwinding of the spring. Thus torque applied to the input shaft 1 can be transmitted to the input dog 5 and thereafter through the finks 7 to the output dog 6 and output shaft 10. When the torque transmitted at the input shaft is increased further, (he output dog 6 moves towards Hie input dog 5 to come into direct contact face to face. The coupling means, such as, the projections 14 on the said dogs, engage with each other such that further increments in torque will be transmitted directly between the dogs 5 and 6, limiting the forces on the links 7 and spring 9 as illustrated bv Fig.5 (the spring 9 has not been shown for the sake of clarity). It will be seen that no torque can be transmitted from the output shaft 10 to the input shaft 1 whereas torque can be transmitted from the input shaft 1 to the putput shaft 10. Furthermore when no torque is applied to the input shaft Ithe output shaft: 10 is effectively locked in position by the ja-ws 13. There is thus no loss of energy either on account of applying or releasing brakes. For smooth functioning it is necessary to have a resisting torque on the output shaft 10 at all times, to avoid chatter of the jaws by alternate engagement, disengagement and consequent wear. There are applications where, at times, the desired motion is in the direction of tiie load torque as when a crane is lowering a load, or when a vehicle is running down-hill JJI such apphcations another variant of the invention in which a disc brake or cone clutch type of brake to hold the output dog (6) to the fixed bearing bracket (11) by spring pressure is used instead of the jaws. In this case it is the friction between the male and female cones that provide the holding force. This would enable the motor coupled to the input shaft (t) to control the degree of braking. The input torque subtracts from me spring force, which is forcing the cones together and so controlling input torque controls the braking force. The output shaft (10) would of course rotate in synchronism with the input shaft (10) in this variant also and the output would stop when the input ceases. It will be appreciated that various other embodiments are possible without departing from the scope and ambit of the invention. We Claim: 1. An automatic locking device for preventing reverse power flow in rotary power transmission comprising a power input shaft connected to a power output shaft; restraining means for preventing the output shaft from rotating when no torque is applied to the 'input shaft; an input member mounted on the input shaft and an output meniber mounted on the output shaft, said members having coupling means for coupling them together when brought into contact with each other, on a torque being iipphed to the input shaft; comjecting means connecting the mput member to the output member for enabling the output shaft to be initially driven by the input shaft until the input and output number are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is initially transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, the torque causes the output member to be drawn by the connecting means towards the input member so as to tome into contact, and couple therewith, to enable the output shaft to be driven directly by the coupled input and output members. 2. A device as claimed in Claim 1, wherein internal splines of the output member engage with external splines on the output shaft 3. A device as claimed in any one of Claim 1 and Claim 2., wherein the mput anil output members are input ami output dogs. 4. A device as claimed in anyone of the preceding Claims wherein the coupling means consist of projections provided on the input and output members. 5. A device as claimed in anyone of the preceding, Claims wherein the connecting means consists of a plurality of hall ended links whose ends are anchored to the input and output members. 6. A device as claimed in anyone of the preceding Claims wherein the resilient means consists of a compression spring,. 7. A device as claimed in anyone of the preceding Claims wherein the restraining means consists of jaws with one set of the teeth provided on the output member and the other set on an adjacent support. 8. A device as claimed in anyone of the preceding Claims 1 to 6 wherein the restraining means consists of a disk brake to restrain the output means from rotating. 9. A device as claimed in anyone, of the preceding, Claims I to 6 wherein the restraining means consists of a cone clutch type of brake to restrain the output member from rotating. We Claim: 1. An automatic locking device for preventing reverse power flow in rotary power transmission comprising a power input shaft connected to a power output shaft; restraining means for preventing the output shaft from rotating when no torque is applied to the 'input shaft; an input member mounted on the input shaft and an output meniber mounted on the output shaft, said members having coupling means for coupling them together when brought into contact with each other, on a torque being iipphed to the input shaft; comjecting means connecting the mput member to the output member for enabling the output shaft to be initially driven by the input shaft until the input and output number* are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is initially transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, the torque causes the output member to be drawn by the connecting means towards the input member so as to tome into contact, and couple therewith, to enable the output shaft to be driven directly by the coupled input and output members. 2. A device as claimed in Claim 1, wherein internal splines of the output member engage with external splines on the output shaft 3. A device as claimed in any one of Claim 1 and Claim 2., wherein the mput anil output members are input ami output dogs. 4. A device as claimed in anyone of the preceding Claims wherein the coupling means consist of projections provided on the input and output members. 5. A device as claimed in anyone of the preceding, Claims wherein the connecting means consists of a plurality of hall ended links whose ends are anchored to the input and output members. 6. A device as claimed in anyone of the preceding Claims wherein the resilient means consists of a compression spring,. 7. A device as claimed in anyone of the preceding Claims wherein the restraining means consists of jaws with one set of the teeth provided on the output member and the other set on an adjacent support. 8. A device as claimed in anyone of the preceding Claims 1 to 6 wherein the restraining means consists of a disk brake to restrain the output means from rotating. 9. A device as claimed in anyone, of the preceding, Claims I to 6 wherein the restraining means consists of a cone clutch type of brake to restrain the output member from rotating.

Full Text

Ibis invention relates to an automatic locking device for preventing reverse power flow in rotary power transmission.
In. many applications a motor has to move a load and hold the load in. a fixed position either by employing a power brake or by controlling the motor current to prevent gravity or momentum from moving the Load. Solenoid operated brakes, worm gear reducers are solutions; however these mechanisms, consume power and are otherwise not efficient, so much so when a large power is involved this can cause substantial energy, lo%&.
This invention therefore proposes an automatic locking device for preventing reverse power flow in rotary power transmission without incurring energj' loss either when the load is bemg driven by a motor or other prune mover or when the transmission shaft is tacked against YoUtisn.
An automatic locking device for preventing reverse power flow in rotar}' power transmission according to this invention^ comprises a power input shaft connected to a power output shaft; restraining means SOT preventing the output shaft from rotating when no torque is applied to the input shaft; an input member mounted on the input shaft and an output member mounted on the output shaft, said members having coupling means for coupling them together when brought into contact with each other, on a torque being applied to the input shaft-, connecting means connecting the input member to the output member

for enabling tne output shatt to be initially driven by the input shaft until the input and output members are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is imtiaUy transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, causes the output member to be drawn by the connecting means towards the input member so as to come in contact, and couple therewith, to enable the output shaft to be driven dh-ectiy by the coupled input and output members.
This invention will now he described with reference to he accompanying drawings which illustrate, by way of example and not by way of limitation one of possible embodiments of the device proposed herein,
Vie. 1 illustrating a general view in elevation of the embodiment
Fi1£. 2 illustrating an exploded view of the embodiment
Fig. 3 illustrating another general view of the embodiment
tig. 4 illustrating a view in perspective of the embodiment from the
output end;
and
I'ig. 5 illustrating a view in perspective of the embodiment from the
input end.
The embodiment has a power input shaft 1 supported hy two ball bearings 2 inside bearing bracket 3 fixed to the frame 4. The input

member, which is the input dog 5, is linked to the output member, -which is the output dog 6, by connecting means which are two or more bail ended links 7, whose ends are anchored to the input dog and output dog respectively by split spherical concave sockets 8 bolted to the periphery of (he input dog and output dog. The said links 7 are thus free to swing in ail directions about their anchor points on the dogs. Resilient means, such as, the compressfon spring 9 disposed between the input and output members, exert a thrust tending to keep the said input dog and output dog apart, with the finks 7 in tension.
The input dog 5 is fixed to the input shaft I by a key. The output shaft 1Q vs su\\vwvte*A «n ball beatin&s I inswle the hiring bvacket 11 which is fixed to the frame 4. The said output shaft 10 has splines on it. The output dog 6 is assembled on to the output shaft 10 such that it is free to slide along the output shaft 10 but is constrained to rotate with it since the internal splines of the output dog 6 engage with the external splines of the output shaft 10.
Fig. I illustrates the position when no torques is exerted on the input shaft 1.
One side of the output dog 6 and an adjacent support, such as, the adjacent side of the hearing bracket 11, has jaws 13 which arc engaged together by the force exerted by the compression spring 9. It is not possible to rotate output shaft 10 because it would have to rotate output dog 6 too and that is not possible as the jaws 13 on the output dog 6 and stationary bracket 11 are meshed together. Figs. 3 and 4 show the

angular displacements caused by (he links 7 on the input dog 5 pulling the output dog 6 towards the input dog 5, compressing the spring 9 resulting in the disengagement of jaws 13. A thrust bearing 1Z at the seating of the spring 9 on the input dog 5 ensures that the spring does not cause any torque due to winding or unwinding of the spring. Thus torque applied to the input shaft 1 can be transmitted to the input dog 5 and thereafter through the finks 7 to the output dog 6 and output shaft 10.
When the torque transmitted at the input shaft is increased further, (he output dog 6 moves towards Hie input dog 5 to come into direct contact face to face. The coupling means, such as, the projections 14 on the said dogs, engage with each other such that further increments in torque will be transmitted directly between the dogs 5 and 6, limiting the forces on the links 7 and spring 9 as illustrated bv Fig.5 (the spring 9 has not been shown for the sake of clarity).
It will be seen that no torque can be transmitted from the output shaft 10 to the input shaft 1 whereas torque can be transmitted from the input shaft 1 to the putput shaft 10. Furthermore when no torque is applied to the input shaft Ithe output shaft: 10 is effectively locked in position by the ja-ws 13. There is thus no loss of energy either on account of applying or releasing brakes.
For smooth functioning it is necessary to have a resisting torque on the output shaft 10 at all times, to avoid chatter of the jaws by alternate engagement, disengagement and consequent wear.

There are applications where, at times, the desired motion is in the direction of tiie load torque as when a crane is lowering a load, or when a vehicle is running down-hill JJI such apphcations another variant of the invention in which a disc brake or cone clutch type of brake to hold the output dog (6) to the fixed bearing bracket (11) by spring pressure is used instead of the jaws. In this case it is the friction between the male and female cones that provide the holding force. This would enable the motor coupled to the input shaft (t) to control the degree of braking. The input torque subtracts from me spring force, which is forcing the cones together and so controlling input torque controls the braking force. The output shaft (10) would of course rotate in synchronism with the input shaft (10) in this variant also and the output would stop when the input ceases.
It will be appreciated that various other embodiments are possible without departing from the scope and ambit of the invention.

We Claim:
1. An automatic locking device for preventing reverse power flow in rotary power transmission comprising a power input shaft connected to a power output shaft; restraining means for preventing the output shaft from rotating when no torque is applied to the 'input shaft; an input member mounted on the input shaft and an output meniber mounted on the output shaft, said members having coupling means for coupling them together when brought into contact with each other, on a torque being iipphed to the input shaft; comjecting means connecting the mput member to the output member for enabling the output shaft to be initially driven by the input shaft until the input and output number* are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is initially transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, the torque causes the output member to be drawn by the connecting means towards the input member so as to tome into contact, and couple therewith, to enable the output shaft to be driven directly by the coupled input and output members.
2. A device as claimed in Claim 1, wherein internal splines of the output member engage with external splines on the output shaft
3. A device as claimed in any one of Claim 1 and Claim 2., wherein the mput anil output members are input ami output dogs.

4. A device as claimed in anyone of the preceding Claims wherein
the coupling means consist of projections provided on the input
and output members.
5. A device as claimed in anyone of the preceding, Claims wherein
the connecting means consists of a plurality of hall ended links
whose ends are anchored to the input and output members.
6. A device as claimed in anyone of the preceding Claims wherein
the resilient means consists of a compression spring,.
7. A device as claimed in anyone of the preceding Claims wherein
the restraining means consists of jaws with one set of the teeth
provided on the output member and the other set on an adjacent
support.
8. A device as claimed in anyone of the preceding Claims 1 to 6
wherein the restraining means consists of a disk brake to restrain
the output means from rotating.
9. A device as claimed in anyone, of the preceding, Claims I to 6
wherein the restraining means consists of a cone clutch type of
brake to restrain the output member from rotating.

We Claim:
1. An automatic locking device for preventing reverse power flow in rotary power transmission comprising a power input shaft connected to a power output shaft; restraining means for preventing the output shaft from rotating when no torque is applied to the 'input shaft; an input member mounted on the input shaft and an output meniber mounted on the output shaft, said members having coupling means for coupling them together when brought into contact with each other, on a torque being iipphed to the input shaft; comjecting means connecting the mput member to the output member for enabling the output shaft to be initially driven by the input shaft until the input and output number* are coupled together; resilient means disposed between the input and output members, exerting a thrust tending to keep the said members apart, the arrangement being such that a torque applied to the input shaft is initially transmitted to the output shaft through the input member, the connecting means and the output member, and simultaneously, thereafter, the torque causes the output member to be drawn by the connecting means towards the input member so as to tome into contact, and couple therewith, to enable the output shaft to be driven directly by the coupled input and output members.
2. A device as claimed in Claim 1, wherein internal splines of the output member engage with external splines on the output shaft
3. A device as claimed in any one of Claim 1 and Claim 2., wherein the mput anil output members are input ami output dogs.

4. A device as claimed in anyone of the preceding Claims wherein
the coupling means consist of projections provided on the input
and output members.
5. A device as claimed in anyone of the preceding, Claims wherein
the connecting means consists of a plurality of hall ended links
whose ends are anchored to the input and output members.
6. A device as claimed in anyone of the preceding Claims wherein
the resilient means consists of a compression spring,.
7. A device as claimed in anyone of the preceding Claims wherein
the restraining means consists of jaws with one set of the teeth
provided on the output member and the other set on an adjacent
support.
8. A device as claimed in anyone of the preceding Claims 1 to 6
wherein the restraining means consists of a disk brake to restrain
the output means from rotating.
9. A device as claimed in anyone, of the preceding, Claims I to 6
wherein the restraining means consists of a cone clutch type of
brake to restrain the output member from rotating.

Documents:

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Patent Number

268475

Indian Patent Application Number

384/CHE/2009

PG Journal Number

36/2015

Publication Date

04-Sep-2015

Grant Date

31-Aug-2015

Date of Filing

24-Feb-2009

Name of Patentee

CENTRE FOR DEVELOPMENT OF ADVANCED COMPUTING

Applicant Address

TECHNOLOGY PROMOTION CENTRE 2ND FLOOR, CHENNANKARA BUILDING, VELLAYAMBALAM, THIRUVANANTHAPURAM - 695033 KERALA

Inventors:

#	Inventor's Name	Inventor's Address
1	RATHEESH RAVI	C-DAC, 2ND FLOOR, CHENNANKARA BUILDING, VELLAYAMBALAM, THIRUVANANTHAPURAM
2	DEVAKI KRISHNA WARRIER	C-DAC, 2ND FLOOR, CHENNANKARA BUILDING, VELLAYAMBALAM, THIRUVANANTHAPURAM

PCT International Classification Number

F16D 2510

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA