1. A synchronizer clutch assembly comprising a clutch hub assembly non-rotatably but axially movably mounted on a torque delivery shaft, at least one gear assembly axially spaced from the hub assembly and journally mounted on the shaft so as to be rotatable independent thereof, one of the hub assembly and the at least one gear assembly having a conical friction surface formed thereon, at least one synchronizer ring positioned between the hub assembly and the at least one gear assembly, the or each synchronizer ring being housed within an annular recess formed in the other of the hub assembly and the at least one gear assembly and coupled to the other of the hub assembly and the at least one gear assembly for rotation therewith and having a complementary conical friction surface formed thereon which is engageable with the conical friction surface of the one of the hub assembly and the at least one gear assembly in order create a drive coupling therebetween, characterized in that the or each synchronizer ring is composed of a plurality of separate arcuate segments arranged in a ring, and movable between a first expanded configuration in which the synchronizer ring has a first radius and a second contracted configuration in which the ring has a second radius and having biasing means associated with the or each synchronizer ring which urges said segments into the other of said first and second configurations in which the conical friction surface of the or each ring is disengaged from the friction surface of the one of the hub assembly and the gear assembly, movement of the hub assembly towards the at least one gear assembly urging the segments of the or each synchronizer ring, into one of said first and second configurations so that the conical friction surface of the ring is pressed against the friction surface of the one or the hub assembly and the gear assembly, thereby drivingly coupling the hub assembly to the at least one gear assembly.
2. A synchronizer clutch assembly according to claim 1, wherein each segment includes a plurality of radial tabs which engage complementarily shaped pockets formed in the other of the hub assembly and the gear assembly so as to non-rotatably couple the segments thereto.
3. A synchronizer clutch assembly according to claim 1, wherein the one of the hub assembly and the gear assembly has an external conical friction surface formed therein which is engageable by an internal conical friction surface formed on the at least one synchronizer ring, the other of the hub assembly and the gear assembly co-operating with the or each synchronizer ring to press said segments radially inwardly towards their second contracted configuration and into engagement with said external friction surface upon axial movement of the hub assembly towards the gear assembly.
4. A synchronizer clutch assembly according to claim 3, wherein said biasing means urges said segments into their first, expanded configuration.
5. A synchronizer clutch assembly according to claim 3, wherein the other of the hub assembly and the gear assembly limits the radial expansion of the synchronizer ring.
6. A synchronizer clutch assembly according to claim 3, wherein the other of the hub assembly and the gear assembly includes inclined surfaces which engage with the segments and urge them toward their contracted configuration upon axial movement of the hub assembly toward the gear assembly.
7. A synchronizer clutch assembly according to claim 1, wherein said biasing means comprises a separating spring positioned between adjacent ring segments which urges said segments apart circumferentially.
8. A synchronizer clutch according to claim 1, wherein the one of the hub assembly and the gear assembly has an internal friction surface formed thereon which is engageable by an external conical friction surface formed on the at least one synchronizer ring, the other of the hub assembly and the gear assembly co-operating with said at least one synchronizer ring to press said segments thereof radially outwardly towards their first expanded configuration and into engagement with said internal friction surface upon axial movement of the hub assembly towards the gear assembly.
9. A synchronizer clutch according to claim 8, wherein said biasing means urges said segments of said at least one synchronizer ring into their second contracted configuration.
10. A synchronizer clutch assembly according to claim 8, wherein the other of the hub assembly and the gear assembly includes inclined surfaces which engage with the segments to urge them toward their expanded configuration upon axial movement of the hub assembly toward the gear assembly.
11. A synchronizer clutch according to claim 1, wherein said biasing means comprises a spring clip which extends around the outside of the segments and urges them radially inward.
12. A synchronizer clutch according to claim 1, wherein the other of the hub assembly and the gear assembly limits the radial contraction of said at least one synchronizer ring.
13. A synchronizer clutch assembly according to claim 1, wherein a return spring is provided between the one of the hub assembly and the or each gear assembly and the synchronizer ring which urges the synchronizer ring axially away from said one of the hub assembly and the or each gear assembly.
14. A synchronizer clutch assembly according to claim 13, wherein the return spring is a compression spring.
15. A synchronizer clutch assembly according to claim 13, wherein a spring plate is located between the return spring and the synchronizer ring.
16. A synchronizer clutch assembly according to claim 1, wherein the hub assembly has a central through opening in which are formed a plurality of teeth which, engage with splines formed on the outer surface of the shaft to rotatably couple the hub assembly to the shaft.
17. A synchronizer clutch assembly according to claim 1, further including a second gear assembly which is journal mounted on the shaft, the hub assembly being position between the first and the second gear assemblies and having a second synchronizer ring positioned between the hub assembly and the second gear assembly.
18. A synchronizer clutch assembly according to claim 1, wherein a pair of segmented synchronizer clutch rings are coupled to the other of the hub assembly and the or each gear assembly for rotation therewith, one of said rings having an internal conical friction surface for engagement with a complementary external friction surface formed on the one of the hub assembly and the at least one gear assembly and the other of said rings having an external conical friction surface for engagement with a complementary internal friction surface formed on the one of the hub assemblies and the at least one gear assembly, whereby the drive coupling between said hub assembly and the or each gear assembly is effected through both of said pair of rings simultaneously.
19. A synchronizer clutch assembly comprising a clutch hub assembly non-rotatably but axially movably mounted on a torque delivery shaft, at least one gear assembly axially spaced from the hub assembly and journally mounted on the shaft so as to be rotatable independent thereof, one of the hub assembly and the at least one gear assembly having a conical friction surface formed thereon, at least one synchronizer ring positioned between the hub assembly and the at least one gear assembly, the or each synchronizer ring being coupled to the other of the hub assembly and the at least one gear assembly for rotation therewith and having a complementary conical friction surface formed thereon which is engageable with the conical friction surface of the one of the hub assembly and the at least one gear assembly in order create a drive coupling therebetween, characterized in that the or each synchronizer ring is composed of a plurality of separate arcuate segments each including a plurality of radial tabs which engaged complementarily shaped pockets formed in the other of the hub assembly and the gear assembly so as to non-rotatably couple the segments together, said segments arranged in a ring, and movable between a first expanded configuration in which the synchronizer ring has a first radius and a second contracted configuration in which the ring has a second radius and having biasing means associated with the or each synchronizer ring which urges said segments into the other of said first and second configurations in which the conical friction surface of the or each ring is disengaged from the friction surface of the one of the hub assembly and the gear assembly, movement of the hub assembly towards the at least one gear assembly urging the segments of the or each synchronizer ring, into one of said first and second configurations so that the conical friction surface of the ring is pressed against the friction surface of the one or the hub assembly and the gear assembly, thereby drivingly coupling the hub assembly to the at least one gear assembly.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for handling suspicious downloadables, comprising:
receiving a downloadable;
scanning the downloadable to identify suspicious computer operations therein; and
if at least one suspicious computer operation is identified, then:
overwriting the suspicious computer operations with substitute computer operations; and
appending monitoring program code to the downloadable thereby generating a modified downloadable, wherein the monitoring program code includes program instructions for validating input parameters for the suspicious computer operations during run-time of the downloadable.
2. The method of claim 1, wherein the substitute computer operations validate their input parameters, and indicate if their input parameters are not successfully validated.
3. The method of claim 2, wherein the substitute computer operations indicate if their input parameters are not successfully validated by invoking an alert.
4. The method of claim 2, wherein the substitute computer operations indicate if their input parameters are not successfully validated by generating a warning text message.
5. The method of claim 1, wherein the monitoring code further includes program instructions for replacing invalid input parameters with valid input parameters in the suspicious computer operations.
6. The method of claim 1, further comprising executing the modified downloadable.
7. The method of claim 6, wherein said executing comprises executing the modified downloadable in a secure environment.
8. The method of claim 1, wherein said receiving comprises receiving the downloadable in transit to an intended destination computer, the method further comprising transmitting the modified downloadable to the destination computer.
9. The method of claim 1, wherein said receiving comprises receiving the downloadable in transit to an intended destination computer, the method further comprising preventing the downloadable from executing on the destination computer if said validating fails.
10. The method of claim 1, wherein said receiving comprises receiving the downloadable in transit to an intended destination computer, the method further comprising consulting a security policy to determine whether to forward the downloadable to the destination computer if said validating fails.
11. The method of claim 1, wherein said validating input parameters comprises comparing actual input parameters to the suspicious computer operations with at least one descriptor of valid input parameters for the suspicious computer operations.
12. The method of claim 1, wherein said validating input parameters comprises comparing actual input parameters to the suspicious computer operations with at least one descriptor of invalid input parameters for the suspicious computer operations.
13. The method of claim 1, wherein said scanning comprises accessing a dictionary of suspicious computer operations.
14. The method of claim 1, wherein said validating comprises accessing a dictionary of valid input parameters.
15. The method of claim 1, wherein said validating comprises accessing a dictionary of invalid input parameters.
16. The method of claim 1, wherein the downloadable is JavaScript program code.
17. The method of claim 1, wherein the downloadable is VBScript program code.
18. The method of claim 1, wherein the downloadable is Flash object compiled program code, the method further comprising de-compiling the Flash object compiled program code to derive source code therefrom.
19. The method of claim 1, wherein the downloadable is applet program code, the method further comprising de-compiling the applet program code to derive source code therefrom.
20. A computer security system, comprising:
a receiver for receiving a downloadable;
a scanner, coupled with said receiver, for scanning the downloadable to identify suspicious computer operations therein;
a code modifier, coupled with said scanner, for overwriting the suspicious computer operations with substitute computer operations, if at least one suspicious computer operation is identified by said scanner, and for appending monitoring program code to the downloadable thereby generating a modified downloadable, if at least one suspicious computer operation is identified by said scanner; and
a processor, coupled with said code modifier, for executing programmed instructions,
wherein the monitoring program code includes program instructions for said processor to validate input parameters for the suspicious computer operations during run-time of the downloadable.
21. The security system of claim 20, wherein the substitute computer operations validate their input parameters, and indicate if their input parameters are not successfully validated.
22. The security system of claim 21, wherein the substitute computer operations indicate if their input parameters are not successfully validated by invoking an alert.
23. The security system of claim 21, wherein the substitute computer operations indicate if their input parameters are not successfully validated by generating a warning text message.
24. The security system of claim 20, wherein the monitoring code further includes program instructions for said processor to replace invalid input parameters with valid input parameters in the suspicious computer operations.
25. The security system of claim 20, wherein said processor executes the modified downloadable.
26. The security system of claim 25, wherein said processor executes the modified downloadable in a secure environment.
27. The security system of claim 20, wherein said receiver receives the downloadable in transit to an intended destination computer, the system further comprising a transmitter for transmitting the modified downloadable to the destination computer.
28. The security system of claim 20, wherein said receiver receives the downloadable in transit to an intended destination computer, and wherein said processor prevents the downloadable from executing on the destination computer if said processor fails to validate the input parameters.
29. The security system of claim 20, wherein said receiver receives the downloadable in transit to an intended destination computer, and wherein said processor consults a security policy to determine whether to forward the downloadable to the destination computer if said validating fails.
30. The security system of claim 20, wherein the monitoring program code includes program instructions for said processor to compare actual input parameters to the suspicious computer operations with at least one descriptor of valid input parameters for the suspicious computer operations.
31. The security system of claim 20, wherein the monitoring program code includes program instructions for said processor to compare actual input parameters to the suspicious computer operations with at least one descriptor of invalid input parameters for the suspicious computer operations.
32. The security system of claim 20, wherein said scanner accesses a dictionary of suspicious computer operations.
33. The security system of claim 20, wherein the monitoring program code includes program instructions for said processor to access a dictionary of valid input parameters.
34. The security system of claim 20, wherein the monitoring program code includes program instructions for said processor to access a dictionary of invalid input parameters.
35. The security system of claim 20, wherein the downloadable is JavaScript program code.
36. The security system of claim 20, wherein the downloadable is VBScript program code.
37. The security system of claim 20, wherein the downloadable is Flash object compiled program code, and wherein said scanner de-compiles the program code to derive source code therefrom.
38. The security system of claim 20, wherein the downloadable is applet compiled program code, and wherein said scanner de-compiles the program code to derive source code therefrom.
39. A method for handling suspicious downloadables, comprising:
receiving a downloadable; and
appending monitoring program code to the downloadable thereby generating a modified downloadable, wherein the monitoring program code includes program instructions:
for identifying suspicious computer operations during run-time of the downloadable;
for overwriting the suspicious computer operations with substitute computer operations during run-time of the downloadable; and
for validating input parameters for the suspicious operations during run-time of the downloadable.
40. The method of claim 39, wherein the substitute computer operations validate their input parameters, and indicate if their input parameters are not successfully validated.
41. The method of claim 39, wherein said identifying suspicious computer operations comprises comparing computer operations in the downloadable with a list of pre-designated computer operations.
42. The method of claim 39, wherein said receiving comprises receiving the downloadable in transit to an intended destination computer, the method further comprising transmitting the modified downloadable to the destination computer if said validating is successful.
43. The method of claim 39, wherein the downloadable is JavaScript program code.
44. The method of claim 39, wherein the downloadable is VBScript program code.
45. The method of claim 39, wherein the downloadable is Flash object compiled program code, the method further comprising de-compiling the Flash object compiled program code to derive source code therefrom.
46. The method of claim 39, wherein the downloadable is applet program code, the method further comprising de-compiling the applet program code to derive source code therefrom.
47. A computer security system, comprising:
a receiver for receiving a downloadable;
a code modifier, coupled with said scanner, for appending monitoring program code to the downloadable thereby generating a modified downloadable; and
a processor, coupled with said code modifier, for executing programmed instructions,
wherein the monitoring program code includes program instructions for said processor:
to identify suspicious computer operations during run-time of the downloadable;
to overwrite the suspicious computer operations with substitute computer operations during run-time of the downloadable; and
to validate input parameters for the suspicious computer operations during run time of the downloadable.
48. The security system of claim 47, wherein the substitute computer operations cause said processor to validate their input parameters, and to indicate if their input parameters are not successfully validated.
49. The security system of claim 47, wherein the monitoring program code further includes program instructions for said processor to compare computer operations in the downloadable with a list of pre-designated computer operations.
50. The computer security system of claim 47, wherein said receiver receives the downloadable in transit to an intended destination computer, the system further comprising a transmitter for transmitting the modified downloadable to the destination computer if said processor successfully validates the input parameters for the suspicious computer operations.
51. The computer security system of claim 47, wherein the downloadable is JavaScript program code.
52. The computer security system of claim 47, wherein the downloadable is VBScript program code.
53. The computer security system of claim 47, wherein the downloadable is Flash object compiled program code, and further comprising a de-compiler for de-compiling the Flash object compiled program code to derive source code therefrom.
54. The computer security system of claim 47, wherein the downloadable is applet program code, and further comprising a de-compiler for de-compiling the applet program code to derive source code therefrom.
55. A method for handling suspicious downloadables, comprising:
scanning a downloadable to detect the presence of at least one suspicious computer operation;
dynamically generating during run-time of the downloadable at least one input parameter for the at least one suspicious computer operation detected by said scanning; and
determining whether or not the dynamically generated at least one input parameter corresponds to a safe input parameter for the at least one suspicious computer operation.
56. A computer security system, comprising:
a scanner for scanning a downloadable to detect the presence of at least one suspicious computer operation; and
a processor that executes programmed instructions:
for dynamically generating during run-time of the downloadable at least one input parameter for the at least one suspicious computer operation detected by said scanner; and
for determining whether or not the dynamically generated at least one input parameter corresponds to a safe input parameter for the at least one suspicious computer operation.