WO2008086602A1

WO2008086602A1 - Parachute ground disconnecting device

Info

Publication number: WO2008086602A1
Application number: PCT/CA2008/000070
Authority: WO
Inventors: Nedeljko Miljic
Original assignee: Airborne Systems Canada Ltd.
Priority date: 2007-01-16
Filing date: 2008-01-16
Publication date: 2008-07-24
Also published as: EP2121442A4; EP2121442A1; CA2678621A1

Abstract

The present invention relates to a parachute ground disconnecting device. The device comprises a lock/release mechanism for keeping a link assembly connected to a parachute in a holding position during a predetermined time interval and after elapse of the predetermined time interval for releasing the link assembly when a predetermined portion of a payload force is below a predetermined release threshold. The device is highly advantageous by providing a simple, yet highly flexible, design for numerous payload ranges.

Description

Parachute Ground Disconnecting Device

Field of the Invention

[001] The present invention relates generally to the field of parachute accessories, and in particular to a device for automatically disconnecting a parachuted payload from a parachute upon landing.

Background of the Invention

[002] In parachuting a payload from an airplane it is important that the parachuted payload is securely connected to the parachute during descent. It is also important that the payload is spontaneously disconnected from the parachute upon landing. Unless the payload is spontaneously disconnected from the parachute upon landing there is an unacceptable high risk that the payload is dragged by winds engaging the parachute, making retrieval of the parachuted payload extremely difficult and dangerous, if not impossible. Furthermore, there is a significant danger that the parachuted payload is toppled over while being dragged resulting in damage or loss of the parachuted payload such as a vehicle.

[003] Several parachute ground disconnecting devices have been developed for automatically disconnecting a parachuted load upon landing. Such devices are designed as a coupler between the parachute and the payload for safely connecting the payload to the parachute during descent. Upon landing a payload weight dependent force acting on the parachute ground disconnecting device decreases and the device opens allowing disconnection of the payload form the parachute.

[004] However, when designing a parachute ground disconnecting device there is a significant problem to overcome. During and shortly after parachute deployment transient parachute inflation phenomena generate substantial oscillations of the payload weight dependent force - or tension - acting on the parachute ground disconnecting device. In order for the parachute ground disconnecting device to operate properly it is important that the parachute is reliably released upon landing but also that the payload stays connected to the parachute during parachute inflation. [005] This problem has been successfully overcome by the parachute ground disconnecting device disclosed in US Patent 5,687,931. Here, the parachute ground disconnecting device is kept in a locked position by a timer for a predetermined time interval during the initial portion of deployment, i.e. during the time period of the parachute inflation. After elapse of the predetermined time interval the device is set to disconnect when the tension is below a predetermined threshold before the tension force in the parachute risers falls to zero.

[006] However, while the parachute ground disconnecting device disclosed in US Patent 5,687,931 has proven to be simply operable and reliable, it comprises a substantially large number of moving parts having small manufacturing tolerances resulting in relatively high manufacturing costs and requiring a substantial amount of maintenance.

[007] It would be beneficial to provide a parachute disconnecting device that is simply operable and reliable but is also simple and cost effective to manufacture and to maintain.

Summary of the Invention

[008] It is, therefore, an object of the invention to provide a parachute ground disconnecting device that is simply operable and reliable but is also simple and cost effective to manufacture and to maintain.

[009] In accordance with the present invention there is provided a parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising: a connecting mechanism for connecting the same to one of the parachute and the payload; a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the supporting structure to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the supporting structure is enabled for disconnecting the payload from the parachute; a latch pivotally movable mounted to the supporting structure and having an interacting structure, in the holding position a pivot of the latch and the interacting structure being disposed on opposite sides of the passage, the latch for retaining the link assembly in the holding position and for transferring via the interacting structure a predetermined portion of a payload force acting on the link assembly; a lock/release mechanism mounted to the supporting structure, the lock/release mechanism comprising a holding mechanism for accommodating the interacting structure of the latch and a release element connected to the holding mechanism at a first end, the holding mechanism and the release element being movable in a longitudinal direction in dependence upon the predetermined portion of the payload force, the release element when abutted at a second end located opposite to the first end for moving the holding mechanism such that the latch is released when the predetermined portion of the payload force is below a predetermined first threshold; a timer mechanism mounted to the supporting structure, the timer mechanism having an axle with a cam attached thereto; an interrupter element mounted to the lock/release mechanism such that the interrupter element holds the timer mechanism in a stopped position when the predetermined portion of the payload force is below a predetermined second threshold; a release lever pivotally movable mounted to the supporting structure, the release lever comprising a first and a second end, the first end interacting with the cam, the release lever being pivotally movable between a first position with the second end being disengaged from the release element and a second position with the second end abutting the second end of the release element in dependence upon movemeni of the cam such that after elapse of a predetermined time interval the release lever is moved to the second position.

[0010] In accordance with the present invention there is further provided a parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising a connecting mechanism for connecting the same to one of the parachute and the payload; a lock/release mechanism mounted to the supporting structure, the lock/release mechanism comprising: a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the lock/release mechanism to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the lock/release mechanism is enabled for disconnecting the payload from the parachute; and, a holding mechanism for retaining the link assembly in the holding position and a release element connected to the holding mechanism at a first end, the holding mechanism and the release element being longitudinally movable in dependence upon a payload force, the release element when abutted at a second end located opposite to the first end for moving the holding mechanism such that the link assembly is released when the payload force is below a predetermined first threshold; a timer mechanism mounted to the supporting structure, the timer mechanism having an axle with a cam attached thereto; an interrupter element mounted to the lock/release mechanism such that the interrupter element holds the timer mechanism in a stopped position when the payload force is below a predetermined second threshold; a release lever pivotally movable mounted to the supporting structure, the release lever comprising a first and a second end, the first end interacting with the cam, the release lever being pivotally movable between a first position with the second end being disengaged from the release element and a second position with the second end abutting the second end of the release element in dependence upon movemem. of the cam such that after elapse of a predetermined time interval the release lever is moved to the second position.

[0011] In accordance with the present invention there is yet further provided a parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising: a connecting mechanism for connecting the same to one of the parachute and the payload; a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the supporting structure to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the supporting structure is enabled for disconnecting the payload from the parachute; a latch pivotally movable mounted to the supporting structure and having an interacting structure, in the holding position a pivot of the latch and the interacting structure being disposed on opposite sides of the passage, the latch for retaining the link assembly in the holding position and for transferring via the interacting structure a predetermined portion of a payload force acting on the link assembly; a lock/release mechanism mounted to the supporting structure comprising: a load counteracting mechanism, the load counteracting mechanism being movable in a longitudinal direction in non-linear dependence upon the predetermined portion of the payload force; a holding mechanism pivotally movable mounted to the load counteracting mechanism, the holding mechanism for accommodating the interacting structure of the latch; and, a release element connected to the holding mechanism at a first end, the release element being movable in the longitudinal direction in dependence upon the predetermined portion of the payload force, the release element when abutted at a second end located opposite to the first end for pivotally moving the holding mechanism such that the latch is released when the predetermined portion of the payload force is below a predetermined first threshold, the second end of the release element comprising a substantially flat surface oriented substantially perpendicular to the longitudinal direction; a mechanical timer mechanism comprising an escapement wheel mounted to the supporting structure, the timer mechanism having an axle with a cam attached thereto; an interrupter element mounted to the release element such that the interrupter element interrupter element engages the escapement wheel of the timer mechanism when the predetermined portion of the payload force is below a predetermined second threshold to prevent a gear train of the timer mechanism from movement and disengages the escapement wheel when the payload force is above the predetermined threshold; a release lever pivotally movable mounted to the supporting structure, the release lever comprising a first and a second end, the first end being a substantially flat surface interacting with the cam, the second end comprising an edge having a predetermined radius, the release lever being pivotally movable between a first posilion with the edge being disengaged from the release element and a second position with the edge abutting the substantially flat surface of the second end of the release element in dependence upon movement of the cam such that after elapse of a predetermined time interval the release lever is moved to the second position and wherein the edge of the release lever abuts the substantially flat surface of the second end of the release element such that a force exerted by the release element onto the edge of the release lever results in moment acting around the pivot towards the second position.

Brief Description of the Figures

[0012] Exemplary embodiments of the invention will now be described in conjunction with the following drawings, in which:

[0013] Figures Ia to Ie are simplified block diagrams schematically illustrating a cross-sectional view of a parachute ground disconnecting device according to the invention in different stages of operation;

[0014] Figures If and Ig are simplified block diagrams schematically illustrating a detailed view of the holding mechanism of the parachute ground disconnecting device according to the invention shown in Figs. Ia to Ie;

[0015] Figure 2 is a simplified block diagram schematically illustrating a perspective view of the parachute ground disconnecting device according to the invention;

[0016] Figures 3a to 3c are simplified block diagrams schematically illustrating a side view of a release element and a release lever of the parachute ground disconnecting device according to the invention; and,

[0017] Figure 4 is a simplified block diagram schematically illustrating a cross- sectional view of a parachute ground disconnecting device according to the invention.

Detailed Description of the Invention

[0018] The following description is presented to enable a person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments disclosed, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0019] Referring to Figs. Ia to Ie, a cross sectional view of a parachute ground disconnecting device 100 according to the invention is shown in five stages of operation:

a) rigged before deployment; b) during parachute inflation; c) during steady descent after elapse of predetermined time interval; d) at ground impact; and, e) after release of the parachute.

[0020] The parachute ground disconnecting device 100 comprises a supporting structure 102. Disposed in a lower portion of the supporting structure 102 is a connecting mechanism 104 for connecting the supporting structure 102 to a payload. Alternatively, a parachute is connected to the connecting mechanism 104. However, mounting the connecting mechanism 104 to the parachute results in loss of the parachute ground disconnecting device 100 if the parachute is not recovered. The connecting mechanism 104 is, for example, constructed as a cylindrical bore for accommodating a cylindrical bolt therein. Disposed in an upper portion of the supporting structure 102 is a passage 106 for accommodating - in the holding position - a link assembly 108 therein. The link assembly 108 connects the supporting structure 102 to a parachute and comprises, for example, a cylindrical bolt for accommodation in the passage 106. Further, the passage 106 is designed such that in an open position, as shown in Fig. Ie, disengagement of the link assembly 108 from the supporting structure 102 is enabled for disconnecting the parachute from the payload. For example, the passage 106 comprises a bent channel portion wide enough for enabling unobstructed movement of the link assembly 108 therethrough and an end portion with the end portion being formed to accommodate, in the holding position, the link assembly 108 therein, for example, having walls of cylindrical shape.

[0021] The link assembly 108 is retained in the holding position by a latch 110. The latch 110 is pivotally movable mounted at a first end to the supporting structure 102 in pivot 112, for example, using cylindrical bores for accommodating a cylindrical bolt therein. At a second opposite end the latch 110 has an interacting structure 114, shaped to interact with holding mechanism 118. As shown in Fig. Ia the latch 110 is disposed such that the pivot 112 and the interacting surface 114 are disposed on opposite sides of the passage 106. For example, the latch 110 comprises an indentation 116 of curved shape to accommodate a portion of the surface of a cylindrical bolt of the link assembly 108, for securing the link assembly 108 in the holding position, particularly during parachute inflation, as discussed above.

[0022] The latch 110, in concert with the end portion of the passage 106, retains the link assembly 108 in the holding position, as shown in Fig. Ia, and transfers via the interacting structure 114 a predetermined portion of a payload force acting on the link assembly 108 to the holding mechanism 118. The transferred predetermined portion of the payload force acts substantially along a longitudinal direction 120. For example, the end portion of the passage 106 and the latch 110 are designed such the center of the pivot 112 is disposed at a predetermined distance C to line 160 through the center of the link assembly 108 and the connecting mechanism 104.

[0023] A lock/release mechanism comprises the holding mechanism 118, a load counteracting mechanism 122, and a release element 124. The load counteracting mechanism 122 and the release element 124 are movable along the longitudinal direction 120 in dependence upon the predetermined portion of the payload force, as shown in Fig. Ib. The holding mechanism 118 is connected to the load counteracting mechanism 122 at pivot 126, placed on a longitudinal axis of the load counteracting mechanism 122. The holding mechanism 118 comprises an arm oriented substantially perpendicular to the longitudinal direction having a slot 128 of predetermined length and disposed at a predetermined distance to the pivot 126. The slot 128 accommodates a pin 127 mounted to a first end of the release element 124, allowing pivotal and longitudinal movement between the release element 124 and the holding mechanism 118. The load counteracting mechanism 122 comprises, for example, a spring loaded cylindrical rod with the spring being a non-linear Belleville-type spring, i.e. distance D is related to the predetermined portion of the payload force in a non-linear fashion. The release element 124 comprises, for example, a spring loaded cylindrical rod.

[0024] The parachute ground disconnecting device 100 further comprises a timer mechanism 128 having an axle with a cam 130 attached thereto. For example, the timer mechanism 128 is a mechanical timer mechanism comprising an escapement wheel 132. An interrupter element 134 is mounted to the release element 124. The interrupter element 134 comprises, for example, a thin metal clip shaped such that it is able to interact with teeth of the escapement wheel 132 for holding the timer mechanism 128 in a stopped position by preventing a gear train of the timer mechanism 128 from movement when the predetermined portion of the payload force is below a predetermined timer threshold and to disengage from the escapement wheel 132 when the predetermined portion of the payload force is above the predetermined timer threshold. Alternatively, an electronic timer mechanism such as quartz clockwork in combination with a mechanism comprising an axle is employed with the interrupter element 134 being designed to interrupt power supply to the electronic timer mechanism.

[0025] A release lever 136 is mounted to the supporting structure 102 at pivot 138. The release lever 136 comprises a first end 140, for example, a substantially flat surface, interacting with the cam 130, and a second end 142, for example, an edge having a predetermined radius for abutting a second end 144, for example, a substantially flat surface oriented substantially perpendicular to the longitudinal direction 120, of the release element 124. The release lever 136 is movable around the pivot 138 between a first position with the second end 142 being disengaged from the second end 144 of the release element 124 and a second position with the second end 142 abutting the second end 144 of the release element 124 in dependence upon movement of the cam 130 such that after elapse of a predetermined time interval the release lever 136 is moved into the second position. A spring mechanism 146, for example, a spring loaded plunger or a torsion spring is employed to ensure a touching relationship between the first end 140 and a surface of the cam 130. For example, the pivot 138, the first end 140 and the second end 142 of the release lever 136 form a triangle such that the first end 140 and the second end 142 are moved in a substantially same direction. To ensure that the release lever 136 stays in the second position when the release element 124 exerts a force onto the second end 142 of the release lever 136, the second end 144 of the release element 124 is abutted by the second end 142 of the release lever 136 such that the force exerted by the release element 124 onto the second end 142 of the release lever 136 results in moment acting around the pivot 138 towards the second position. This is realized, for example, by designing the release lever 136 such that the second end 142 of the release lever 136 abuts the second end 144 of the release element 124 in interaction point 148 such that in a direction perpendicular to the longitudinal direction the pivot 138 is located at a predetermined distance E between the interaction point 148 and the first end 140 of the release lever 136, as shown in Fig. Ic. Alternatively, a substantially flat surface of the second end 144 of the release element 124 is oriented at a predetermined angle to the longitudinal direction 120 other than 90° such that its normal is pointing in a substantially same direction as the direction of the movement of the release lever 136 from the first position to the second position. Alternatively, interaction between the cam 130 and the fist end 140 of the release lever 136 is realized using, for example, a pin mounted to the cam 130 which is accommodated in a slot disposed at the first end 140 of the release lever 136 enabling rotating and longitudinal movement therebetween for moving the release lever 136.

[0026] The load counteracting mechanism 122, the release elemeni 124, the timer mechanism 128, and the release lever 136 are, for example, disposed in a housing 150. The housing 150 is, for example, disposed between two parallel plates forming the supporting structure 102, as shown in Fig. 2 - with one plate removed.

[0027] Fig. Ia illustrates the parachute ground disconnecting device 100 according to the invention in a rigged state without load applied, i.e. prior deployment. The device 100 is easily rigged by performing the following steps:

a) winding and setting the timer mechanism 128, for example, by turning the axle comprising the cam 130 to a predetermined time interval - for example 15 seconds - which moves the release lever 136 into the first position and allows the release element 124 to move freely; b) disposing the link assembly 108 in the end portion of the passage 106; and,

c) moving the latch 110 into the holding position while turning the holding mechanism 118 around the pivot 126 to engage the interacting structure 114 of the latch 110, which is facilitated by providing the holding mechanism 118 with a curved surface portion 150 describing a section of a circle around the pivot 126, thus allowing turning of the holding mechanism without moving of the load counteracting mechanism 122.

[0028] Fig. Ib illustrates the parachute ground disconnecting device 100 according to the invention during parachute inflation. Transient parachute inflation phenomena generate substantial oscillations of the predetermined portion of the payload force acting on the link assembly 108 resulting in an oscillating movement of the load counteracting mechanism 122 and the release element 124 in dependence thereupon. When - during this transient phase - the predetermined portion of the payload force is above the predetermined timer threshold, the interrupter element 134 is disengaged from the escapement wheel 132 allowing the timer mechanism to move.

[0029] Fig. Ic illustrates the parachute ground disconnecting device 100 according to the invention during steady descent after elapse of the predetermined time interval. During elapse of the predetermined time interval the cam 130 is rotated such that after elapse of the same the release lever 136 is moved from the first position to the second position for abutting the release element 124.

[0030] Fig. Id illustrates the parachute ground disconnecting device 100 according to the invention at ground impact. When - at ground impact - the predetermined portion of the payload force is decreased to a predetermined release threshold, the second end 144 of the release element 124 is in contact with the second end 142 of the release lever 136, i.e. is abutted by the same. When the predetermined portion of the payload force is further decreased movement of the load counteracting mechanism 122 continues while the release element 124 is stopped causing a pivotal movement of the holding mechanism 118 around the pivot 126 and disengagement of the interacting structure 114 of the latch 110 from the holding mechanism 118. This disengagement occurs before the tension force in the parachute risers falls to zero. [0031] Fig. Ie illustrates the parachute ground disconnecting device 100 according to the invention after release of the parachute. After disengagement of the interacting structure 114 of the latch 110 from the holding mechanism 118 the predetermined portion of the payload force acting on the link assembly causes the latch 110 to rotate around the pivot 112 allowing disengagement of the link assembly 108 from the supporting structure 102 for disconnecting the parachute from the payload.

[0032] In order to prevent disengagement prior to ground contact due to strong oscillations during parachute inflation and descent, the slot 128 of the holding mechanism 118 is L-shaped as shown in Figs. If and Ig. During parachute inflation and descent, the pin 127 is accommodated in a first location of the slot 128, due to the predetermined portion of the payload force acting on the holding mechanism 118, where the pin 127 is abutted by shoulder 129, as shown in Fig. If. By abutting the pin 127, the holding mechanism 118 is prevented from pivotally moving around the pivot 126 and, therefore, disengagement prior to ground contact is prevented. After ground contact - when the predetermined portion of the payload force is decreased to the predetermined release threshold - the pin 127 is moved into a second location, as shown in Fig. Ig. Here, the pin 127 is no longer abutted by the shoulder 129 and pivotal movement of the holding mechanism 118 around pivot 126 is enabled for disengaging the interacting structure 114 of the latch 110 from the holding mechanism 118.

[0033] The parachute ground disconnecting device 100 according to the invention is simply operable and reliable but is also of simple design having a small number of moving parts which are cost effective to manufacture and to maintain.

[0034] A highly advantageous feature of the parachute ground disconnecting device 100 is that it stays in an open position until the timer mechanism 128 is reset, preventing the latch 110 from being closed and, therefore, preventing a user from rigging and loading the parachute ground disconnecting device 100 without re-setting the timer mechanism 128.

[0035] Furthermore, it is possible to use the same timer and lock/release mechanism for a wide range of payloads. This is achieved, for example, by simply changing the geometry of the support structure 102 and the latch 110, i.e. it is possible to use a same timer and lock/release mechanism provided in a housing 150 for a payload of 500 lbs as well as 15,000 lbs, but is not limited thereto.

[0036] Yet further, the parachute ground disconnecting device 100 according to the invention allows simple adjustment of the timer threshold and the release threshold by simply modifying the geometry of the release element 124 and the interrupter element 134. The timer threshold is adjusted by changing the position of the interrupter element 134 along the longitudinal direction 120 which is accomplished, for example, by providing the interrupter element 134 with a slot 170 for variably accommodating a mounting screw therein, as shown in Fig. 3a. The release threshold is adjusted by changing the position of the second end 144 of the release element 124 along the longitudinal direction 120 which is accomplished, for example, by providing a screw mechanism 172, as shown in Fig. 3 a. Alternatively, the second end 142 of the release lever 136 is provided as a separate element 142 A variably mounted to the release lever 136 such that a distance between the pivot 138 and the second end 142 is changed, for example, by providing the second end element 142 A with a slot for variably accommodating a mounting screw therein, as shown in Fig. 3b. Further alternatively, the release element 124 comprises one or more notches 125 for accommodating a portion of the second end 142 of the release lever 136 after elapse of the predetermined time interval for abutting the release element 124, as shown in Fig. 3c. This allows, for example, setting of the timer threshold and the release threshold in a calibration process during manufacture and maintenance and, furthermore, enables operation of the ground disconnecting device over a wider range of payloads.

[0037] Referring to Fig. 4, a parachute ground disconnecting device 200 according to the invention is shown. The parachute ground disconnecting device 200 comprises the same lock/release mechanism and timer mechanism disposed in a housing 202. Disposed in a lower portion of the housing 202 is a connecting mechanism 204 for connecting the housing 202 to a payload. Here, a link assembly 208 is accommodated in a passage 212 of a linking structure 210 mounted to load counteracting mechanism 222. The link assembly 208 is held in the holding position by holding mechanism 218. Except for the above described differences the parachute ground disconnecting device 200 comprises the same components as the device 100 and operates in a same fashion. [0038] Numerous other embodiments of the invention will be apparent to persons skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

ClaimsWhat is claimed is:

1. A parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising: a connecting mechanism for connecting the same to one of the parachute and the payload; a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the supporting structure to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the supporting structure is enabled for disconnecting the payload from the parachute; a latch pivotally movable mounted to the supporting structure and having an interacting structure, in the holding position a pivot of the latch and the interacting structure being disposed on opposite sides of the passage, the latch for retaining the link assembly in the holding position and for transferring via the interacting structure a predetermined portion of a payload force acting on the link assembly; a lock/release mechanism mounted to the supporting structure, the lock/release mechanism comprising a holding mechanism for accommodating the interacting structure of the latch and a release element connected to the holding mechanism at a first end, the holding mechanism and the release element being movable in a longitudinal direction in dependence upon the predetermined portion of the payload force, the release element when abutted at a second end located opposite to the first end for moving the holding mechanism such that the latch is released when the predetermined portion of the payload force is below a predetermined first threshold; a timer mechanism mounted to the supporting structure, the timer mechanism having an axle with a cam attached thereto; an interrupter element mounted to the lock/release mechanism such that the interrupter element holds the timer mechanism in a stopped position when the predetermined portion of the payload force is below a predetermined second threshold; a release lever pivotally movable mounted to the supporting structure, the release lever comprising a first and a second end, the first end interacting with the cam, the release lever being pivotally movable between a first position with the second end being disengaged from the release element and a second position with the second end abutting the second end of the release element in dependence upon movement of the cam such that after elapse of a predetermined time interval the release lever is moved to the second position.

2. A parachute ground disconnecting device as defined in claim 1 wherein the lock/release mechanism comprises a load counteracting mechanism having the holding mechanism pivotally movable attached thereto, the load counteracting mechanism being movable in the longitudinal direction in dependence upon the predetermined portion of the payload force.

3. A parachute ground disconnecting device as defined in claim 2 wherein the holding mechanism comprises an arm oriented substantially perpendicular to the longitudinal direction having an L-shaped slot for accommodating a pin of the release element therein such that in dependence upon the predetermined portion of the payload force pivotal movement of the holding mechanism is one of prevented and enabled.

4. A parachute ground disconnecting device as defined in any one of claims 2 and 3 wherein the load counteracting mechanism comprises a non-linear compression spring.

5. A parachute ground disconnecting device as defined in any one of claims 1 to 4 wherein the interrupter element is mounted to the release element.

6. A parachute ground disconnecting device as defined in any one of claims 1 to 5 wherein the timer mechanism is a mechanical timer mechanism comprising an escapement wheel.

7. A parachute ground disconnecting device as defined in claim 6 wherein the interrupter element engages the escapement wheel of the timer mechanism when the predetermined portion of the payload force is below a predetermined second threshold to prevent a gear train of the timer mechanism from movement and disengages the escapement wheel when the payload force is above the predetermined threshold.

8. A parachute ground disconnecting device as defined in any one of claims 1 to 7 wherein the first end of the release lever interacts with the cam via a touching relationship between a surface of the cam and a surface of the release lever.

9. A parachute ground disconnecting device as defined in claim 8 comprising a spring mechanism acting on the release lever to ensure the touching relationship between the surface of the cam and the surface of the release lever.

10. A parachute ground disconnecting device as defined in claim 9 wherein the spring mechanism comprises a spring loaded plunger.

11. A parachute ground disconnecting device as defined in claim 9 wherein the spring mechanism comprises a torsion spring.

12. A parachute ground disconnecting device as defined in any one of claims 1 to 11 wherein the pivot, the first end and the second end of the release lever form a triangle such that the first end and the second end are moved in a substantially same direction.

13. A parachute ground disconnecting device as defined in claim 12 wherein the second end of the release element is abutted by the second end of the release lever such that a force exerted by the release element onto the second end of the release lever results in moment acting around the pivot towards the second position.

14. A parachute ground disconnecting device as defined in claim 13 wherein the second end of the release lever comprises an edge having a predetermined radius.

15. A parachute ground disconnecting device as defined in claim 14 wherein the second end of the release element comprises a substantially flat surface.

16. A parachute ground disconnecting device as defined in claim 15 wherein the surface is oriented substantially perpendicular to the longitudinal direction.

17. A parachute ground disconnecting device as defined in any one of claims 1 to 16 wherein the lock/release mechanism is mounted to the supporting structure such that the longitudinal direction is oriented at a predetermined angle to a direction along a line through the connecting mechanism and the link assembly in the holding position.

18. A parachute ground disconnecting device as defined in any one of claims 1 to 17 wherein the latch comprises an indentation for retaining a portion of the link assembly therein.

19. A parachute ground disconnecting device as defined in claim 18 wherein an end portion of the passage and the indentation substantially form a bore such that the predetermined portion of payload force acting on the link assembly is transferred via the interacting structure.

20. A parachute ground disconnecting device as defined in any one of claims 1 to 19 wherein the load counteracting mechanism, the release element and Ihe timer mechanism are disposed in a housing mounted to the supporting structure.

21. A parachute ground disconnecting device as defined in claim 20 wherein the support structure comprises two parallel plates mounted together and having the housing mounted therebetween.

22. A parachute ground disconnecting device as defined in any one of claims 1 to 21 wherein the interrupter element is mounted to the lock/release mechanism such that its location is variable along the longitudinal direction.

23. A parachute ground disconnecting device as defined in claim 22 wherein the release element comprises a mechanism for adjusting a distance between its first end and its second end along the longitudinal direction.

24. A parachute ground disconnecting device as defined in claim 22 wherein the release lever comprises a mechanism for adjusting a distance between its pivot and its second end.

25. A parachute ground disconnecting device as defined in any one of claims 1 to 24 wherein the release element comprises at least a notch disposed along the longitudinal direction the at least a notch for accommodating a portion of the second end of the release lever therein after elapse of the predetermined time interval.

26. A parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising a connecting mechanism for connecting the same to one of the parachute and the payload; a lock/release mechanism mounted to the supporting structure, the lock/release mechanism comprising: a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the lock/release mechanism to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the lock/release mechanism is enabled for disconnecting the payload from the parachute; and, a holding mechanism for retaining the link assembly in the holding position and a release element connected to the holding mechanism at a first end, the holding mechanism and the release element being longitudinally movable in dependence upon a payload force, the release element when abutted at a second end located opposite to the first end for moving the holding mechanism such that the link assembly is released when the payload force is below a predetermined first threshold; a timer mechanism mounted to the supporting structure, the timer mechanism having an axle with a cam attached thereto; an interrupter element mounted to the lock/release mechanism such that the interrupter element holds the timer mechanism in a stopped position when the payload force is below a predetermined second threshold; a release lever pivotally movable mounted to the supporting structure, the release lever comprising a first and a second end, the first end interacting with the cam, the release lever being pivotally movable between a first position with the second end being disengaged from the release element and a second position with the second end abutting the second end of the release element in dependence upon movement of the cam such that after elapse of a predetermined time interval the release lever is moved to the second position.

27. A parachute ground disconnecting device as defined in claim 26 wherein the lock/release mechanism comprises a load counteracting mechanism having the holding mechanism pivotally movable attached thereto, the load counteracting mechanism being movable in the longitudinal direction in dependence upon the predetermined portion of the payload force.

28. A parachute ground disconnecting device as defined in claim 27 wherein the load counteracting mechanism comprises a non-linear compression spring.

29. A parachute ground disconnecting device as defined in any one of claims 26 to 28 wherein the interrupter element is mounted to the release element.

30. A parachute ground disconnecting device as defined in any one of claims 26 to 29 wherein the timer mechanism is a mechanical timer mechanism comprising an escapement wheel.

31. A parachute ground disconnecting device as defined in any one of claims 26 to 30 wherein the interrupter element engages the escapement wheel of the timer mechanism when the predetermined portion of the payload force is below a predetermined second threshold to prevent a gear train of the timer mechanism from movement and disengages the escapement wheel when the payload force is above the predetermined threshold.

32. A parachute ground disconnecting device as defined in any one of claims 26 to 31 wherein the first end of the release lever interacts with the cam via a touching relationship between a surface of the cam and a surface of the release lever.

33. A parachute ground disconnecting device as defined in claim 32 comprising a spring mechanism acting on the release lever to ensure the touching relationship between the surface of the cam and the surface of the release lever.

34. A parachute ground disconnecting device as defined in claim 33 wherein the spring mechanism comprises a spring loaded plunger.

35. A parachute ground disconnecting device as defined in claim 33 wherein the spring mechanism comprises a torsion spring.

36. A parachute ground disconnecting device as defined in any one of claims 26 to 35 wherein the first end of the release lever interacts with the cam via a pin of the cam accommodated in a slot disposed at the first end of the release lever.

37. A parachute ground disconnecting device as defined in any one of claims 26 to 36 wherein the pivot, the first end and the second end of the release lever form a triangle such that the first end and the second end are moved in a substantially same direction.

38. A parachute ground disconnecting device as defined in claim 37 wherein the second end of the release element is abutted by the second end of the release lever such that a force exerted by the release element onto the second end of the release lever results in moment acting around the pivot towards the second position.

39. A parachute ground disconnecting device as defined in claim 38 wherein the second end of the release lever comprises an edge having a predetermined radius.

40. A parachute ground disconnecting device as defined in claim 39 wherein the second end of the release element comprises a substantially flat surface.

41. A parachute ground disconnecting device as defined in claim 40 wherein the surface is oriented substantially perpendicular to the longitudinal direction.

42. A parachute ground disconnecting device as defined in any one of claims 26 to 41 wherein the interrupter element is mounted to the lock/release mechanism such that its location is variable along the longitudinal direction.

43. A parachute ground disconnecting device as defined in claim 42 wherein the release element comprises a mechanism for adjusting a distance between its first end and its second end along the longitudinal direction.

44. A parachute ground disconnecting device as defined in claim 42 wherein the release lever comprises a mechanism for adjusting a distance between its pivot and its second end.

45. A parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising: a connecting mechanism for connecting the same to one of the parachute and the payload; a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the supporting structure to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the supporting structure is enabled for disconnecting the payload from the parachute; a latch pivotally movable mounted to the supporting structure and having an interacting structure, in the holding position a pivot of the latch and the interacting structure being disposed on opposite sides of the passage, the latch for retaining the link assembly in the holding position and for transferring via the interacting structure a predetermined portion of a payload force acting on the link assembly; a lock/release mechanism mounted to the supporting structure comprising: a load counteracting mechanism, the load counteracting mechanism being movable in a longitudinal direction in non-linear dependence upon the predetermined portion of the pay load force; a holding mechanism pivotally movable mounted to the load counteracting mechanism, the holding mechanism for accommodating the interacting structure of the latch; and, a release element connected to the holding mechanism at a first end, the release element being movable in the longitudinal direction in dependence upon the predetermined portion of the payload force, the release element when abutted at a second end located opposite to the first end for pivotally moving the holding mechanism such that the latch is released when the predetermined portion of the payload force is below a predetermined first threshold, the second end of the release element comprising a substantially flat surface oriented substantially perpendicular to the longitudinal direction; a mechanical timer mechanism comprising an escapement wheel mounted to the supporting structure, the timer mechanism having an axle with a cam attached thereto; an interrupter element mounted to the release element such that the interrupter element interrupter element engages the escapement wheel of the timer mechanism when the predetermined portion of the payload force is below a predetermined second threshold to prevent a gear train of the timer mechanism from movement and disengages the escapement wheel when the payload force is above the predetermined threshold; a release lever pivotally movable mounted to the supporting structure, the release lever comprising a first and a second end, the first end being a substantially flat surface interacting with the cam, the second end comprising an edge having a predetermined radius, the release lever being pivotally movable between a first position with the edge being disengaged from the release element and a second position with the edge abutting the substantially flat surface of the second end of the release element in dependence upon movement of the cam such that after elapse of a predetermined time interval the release lever is moved to the second position and wherein the edge of the release lever abuts the substantially flat surface of the second end of the release element such that a force exerted by the release element onto the edge of the release lever results in moment acting around the pivot towards the second position.