U.S. patent application number 11/674739 was filed with the patent office on 2010-10-28 for pointing device inertial isolation and alignment mounting system.
This patent application is currently assigned to Honeywell International Inc.. Invention is credited to Richard L. Bissell, Daniel E. Burkholder, John M. Shipman.
Application Number | 20100269681 11/674739 |
Document ID | / |
Family ID | 38283518 |
Filed Date | 2010-10-28 |
United States Patent
Application |
20100269681 |
Kind Code |
A1 |
Shipman; John M. ; et
al. |
October 28, 2010 |
Pointing Device Inertial Isolation and Alignment Mounting
System
Abstract
An inertial isolation and alignment system for a sensitive
component or apparatus affixed to a mortar barrel comprising a
barrel clamp assembly which supports two parallel bearing rail
followers and pointing device cage assembly which supports two
parallel linear bearing rails. The bearing rail followers and
linear bearing rails form a simple sliding contact linear motion
bearing system. The bearing rail followers on the barrel clamp
assembly allow the cage assembly to slide freely along the length
of the linear bearing rails. During firing, the travel vector is
decoupled from the cage assembly by the bearing rail followers as
they move with the barrel along the linear bearing rails leaving
the cage assembly suspended in inertial space. The cage assembly
then accelerates under the force of gravity over the distance of
the displaced travel of the bearing rail followers back to its rest
position landing on dampers, each on a linear bearing rail.
Inventors: |
Shipman; John M.;
(Albuquerque, NM) ; Burkholder; Daniel E.;
(Maurepas, LA) ; Bissell; Richard L.; (Rio Rancho,
NM) |
Correspondence
Address: |
HONEYWELL/S&S;Patent Services
101 Columbia Road, P.O.Box 2245
Morristown
NJ
07962-2245
US
|
Assignee: |
Honeywell International
Inc.
Morristown
NJ
|
Family ID: |
38283518 |
Appl. No.: |
11/674739 |
Filed: |
February 14, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60793169 |
Apr 19, 2006 |
|
|
|
Current U.S.
Class: |
89/42.01 ;
89/37.01; 89/37.05 |
Current CPC
Class: |
F41G 11/004 20130101;
F41F 1/06 20130101; F41G 11/002 20130101 |
Class at
Publication: |
89/42.01 ;
89/37.01; 89/37.05 |
International
Class: |
F41A 23/00 20060101
F41A023/00 |
Claims
1. An inertial isolation and alignment assembly for aligning and
isolating a shock of a sensitive component affixed to a barrel, the
inertial isolation and alignment assembly comprising: a saddle
clamp structure configured to removably affix the inertial
isolation and alignment assembly to the barrel; a cage assembly
affixed to the saddle clamp structure and configured to encase the
sensitive component; and a linear motion bearing system comprising
at least two linear bearing rails and at least two bearing rail
followers, wherein the linear bearing rails and bearing rail
followers cooperate to inertially isolate the cage assembly from
the saddle structure, and wherein the at least two linear bearing
rails are anchored to the cage assembly.
2. The inertial isolation and alignment assembly of claim 1,
wherein the saddle clamp structure comprises clamps.
3. The inertial isolation and alignment of claim 1, wherein each of
the at least two bearing rail followers is configured to accept a
respective one of the at least two linear bearing rails to form a
sliding contact linear motion bearing system.
4. The inertial isolation and alignment assembly of claim 1,
wherein each of the at least two bearing rail followers is
configured to accept a respective one of the at least two linear
bearing rails so that each of the at least two linear bearing rails
is substantially parallel to the mortar barrel.
5. (canceled)
6. The inertial isolation and alignment assembly of claim 1,
further comprising shock dampers disposed at an end of each of the
at least two linear bearing rails.
7. The inertial isolation and alignment assembly of claim 1,
further comprising a quick release mechanism for the cage
assembly.
8. A method for isolating a shock of a sensitive component affixed
to a mortar barrel using an inertial isolation and alignment
assembly, wherein the inertial isolation and alignment assembly
comprises a saddle clamp structure configured to removably affix
the inertial isolation and alignment assembly to the mortar barrel,
a cage assembly affixed to the saddle clamp structure and
configured to encase the sensitive component, and a linear motion
bearing system, wherein the linear motion bearing system comprises
at least two linear bearing rails and at least two bearing rail
followers, wherein the linear bearing rails and bearing rail
followers cooperate to inertially isolate the cage assembly from
the saddle structure, and wherein the at least two linear bearing
rails are anchored to the cage assembly, the method comprising:
sliding the at least two linear bearing rails through the at least
two bearing rail followers when a projectile is fired through the
mortar barrel, thereby causing the cage assembly to be suspended in
inertial space; and dampening a fall of the cage assembly.
9. The method of claim 8, the method further comprising affixing a
saddle structure that contains the at least two bearing rail
followers to the mortar barrel.
10. The method of claim 8, wherein each of the at least two bearing
rail followers is configured to accept a respective one of the at
least two linear bearing rails.
11. The method of claim 8, the method further comprising providing
that the at least two linear bearing rails are substantially
parallel to the mortar barrel.
12. The method of claim 8 wherein dampening comprises providing
shock dampers.
13. The method of claim 8, the method further comprising releasing
the cage assembly from the saddle structure when dismounting the
sensitive component.
Description
RELATED APPLICATIONS
[0001] The present patent application claims priority under 35
U.S.C. .sctn. 119(e) to U.S. Provisional Patent Application Ser.
No. 60/793,169, which was filed Apr. 19, 2006. The full disclosure
of U.S. Provisional Patent Application Ser. No. 60/793,169 is
incorporated herein by reference.
FIELD
[0002] This invention relates to large bore weapons and more
particularly to a method and apparatus for isolating a shock from a
mortar firing event while maintaining the alignment of a sensitive
electronic pointing device for use on a mortar barrel or similar
device.
BACKGROUND
[0003] During the firing of a large bore weapon a significant
reaction force is imparted to the barrel and support structure. A
support structure, which is required to travel a certain distance
before absorbing the load, allows the barrel and its attached
components to undergo a nearly instantaneous high-g acceleration.
Sensitive electronic pointing devices, such as inertial measurement
units (IMUs) or inertial navigation systems (INSs), and their
attachment structures have been destroyed by this extreme
acceleration and deceleration on occasion.
[0004] The present invention is a method and apparatus for
isolating a sensitive electronic device from the barrel recoil
travel using a linear motion bearing mounting system. For example,
Honeywell's Tactical Advanced Land Inertial Navigator (TALIN.TM.)
pointing device requires a mortar mount assembly designed to
provide a stable and protective cage parallel to the center line of
the barrel. The mortar barrel of a 120 mm mortar weapon moves
approximately twelve inches (12'') under a high acceleration,
developing energy of approximately five hundred thousand
foot-pounds (500 k ft-lbs.) and then decelerates to a stop in less
than 0.010 seconds when fired from a base plate in a free standing
configuration. More particularly, this mount needs to provide for
the repeated firing of the mortar weapon without realignment or
mechanical adjustment while maintaining a zero ballistic force
vector on the pointing device.
[0005] Presently, typical PDMAs (pointing device mounting
assemblies) cannot withstand the recoil acceleration force while
attached to a 120 mm mortar barrel when fired. The typical PDMA
experiences catastrophic failure of the steel mounting plates due
to stress in excess of the bending moment of the material of their
construction. This force exceeds the PDMA shock isolators' travel
limit and transfers the shock load into the RLG (ring laser
gyroscope) pointing device, causing internal physical damage.
[0006] Others have tried to solve the problem by designing a
mounting platform for the RLG pointing device which allows the
mortar barrel to recoil while separating the RLG pointing device
from the recoil force through a shaft and sleeve bearing assembly.
There is still hammer shock with this design, however, due to the
loosely coupled parts. This design also lacks the durability
desired for a PDMA.
[0007] A prior art device, described in U.S. Pat. No. 4,336,917,
uses gas driven pistons and gas accumulator/controllers that are
sensor-controlled to maintain position during shock and vibration.
Another prior art device, described in U.S. Pat. No. 6,814,179,
uses shock isolators that are comprised of rubber and polyurethane
foam to absorb shock and vibration.
SUMMARY
[0008] The present invention solves the problem of inertial
isolation by providing a mechanical assembly designed to provide a
linear travel support frame constructed of bearing rail followers
aligned parallel with the barrel reactive force vector and
suspending the mass of the pointing device on linear bearing rails
in a cage assembly that provides and maintains alignment while
allowing the mortar weapon to accelerate and decelerate without
transfer of motion to the suspended pointing device. The pointing
device then returns to its rest position on the linear bearing
mounting system by gravitational force. The parts work together to
isolate the acceleration vector of the mortar barrel from the
TALIN.TM. mass. During firing, the mortar barrel moves the attached
bearing rail followers along the linear bearing rails, without
imparting any acceleration to the cage assembly containing the
TALIN.TM.. The combined linear bearing rails and bearing rail
followers form a simple sliding contact linear motion bearing
system. During the mortar firing recoil, the force vector loads are
directionally decoupled between the bearing rail followers and the
linear bearing rails in their axis of travel. This prevents the
mass of the RLG pointing device from inertially loading the cage
assembly in excess of its out of plane deflection limits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Various embodiments are described herein with reference to
the following drawings. Certain aspects of the drawings are
depicted in a simplified way for reason of clarity. Not all
alternatives and options are shown in the drawings and, therefore,
the invention is not limited in scope to the content of the
drawings. In the drawings:
[0010] FIG. 1 is a perspective view of the preferred inertial
isolation and alignment assembly mounted on a mortar weapon;
[0011] FIG. 2 is a perspective view of the preferred inertial
isolation and alignment assembly of FIG. 1 in the extended
position;
[0012] FIG. 3 is a perspective view of the preferred inertial
isolation and alignment assembly of FIG. 1 in the ready-to-fire
position;
[0013] FIGS. 4A and 4B are front and side views of the preferred
barrel clamp assembly; FIGS. 5A and 5B are front and side views of
the preferred cage assembly;
[0014] FIG. 6 shows the preferred inertial isolation and alignment
assembly in the pre-fire condition; and
[0015] FIG. 7 shows the preferred inertial isolation and alignment
assembly immediately after a firing condition.
DETAILED DESCRIPTION
[0016] Disclosed is a preferred embodiment of an inertial isolation
and alignment assembly 100 for mounting a sensitive component such
as a pointing device to a mortar weapon, or the like. FIG. 1 shows
a perspective view of inertial isolation and alignment assembly
100, affixed to a mortar weapon comprising a base plate 110, mortar
barrel 120, and bipod 130. The inertial isolation and alignment
assembly 100 is affixed to the underside of mortar barrel 120. As
can be seen, inertial isolation and alignment assembly 100 consists
of a barrel clamp assembly 200 to secure inertial isolation and
alignment assembly 100 to mortar barrel 120, and a cage assembly
300 to encase a pointing device 310, such as a TALIN.TM. pointing
device.
[0017] FIG. 2 depicts a perspective view of the preferred inertial
isolation and alignment assembly 100 in the extended position. The
first part of this embodiment is barrel clamp assembly 200 which
mounts to mortar barrel 120. Barrel clamp assembly 200 includes
bearing rail followers 210, which position linear bearing rails 340
parallel to mortar barrel 120. The second part of this embodiment
is cage assembly 300, which encases pointing device 310 and anchors
linear bearing rails 340. The top surface 212 and bottom surface
214 of bearing rail followers 210, in combination with the linear
bearing rails 340, form the basis of the sliding contact linear
motion bearing system, similar to the slide actions of
semi-automatic rifles or pistols.
[0018] FIG. 3 shows a perspective view of the preferred inertial
isolation and alignment assembly 100 of FIG. 1 in the ready-to-fire
position. It illustrates how linear bearing rails 340 of cage
assembly 300 slide through bearing rail followers 210 of barrel
clamp assembly 200, effecting the simple sliding contact linear
motion bearing system.
[0019] FIG. 4A shows a front view of the preferred barrel clamp
assembly 200. Barrel clamp assembly 200 comprises a saddle
structure 220 and a saddle clamp structure 230 with saddle clamp
bolts 240. Saddle structure 220 has saddle extensions 222 with
bearing rail followers 210. Saddle structure 220 and saddle
extensions 222 form a one piece "C" channel structure. However,
saddle extensions 222 could also be separate mounting blocks
permanently affixed to saddle structure 220. Saddle clamp structure
230 is affixed to saddle extensions 222 with saddle clamp bolts
240. Saddle extensions 222 are drilled and tapped from the top side
at each corner to receive saddle clamp bolts 240. This entire
saddle structure 220 is preferably machined from a solid piece of
bar stock (such as 4340 steel, for example) to provide uniform
strength and stress distribution throughout the structure. Saddle
structure 220 can also be manufactured from aluminum, titanium,
plastic, composite, or other materials able to withstand the forces
exerted by a particular mortar weapon, and the temperature rise of
the mortar barrel experienced during firing.
[0020] Barrel clamp assembly 200 is subjected to the acceleration
and firing shock of more than two thousand g's on the 120 mm mortar
weapon during firing. This shock, coupled with torsional stress
from a bolt down force of more than 95 foot-pounds across the
diagonal length of barrel clamp assembly 200 and the temperature
rise from repeated firings, requires additional structure for the
barrel clamp assembly 200 to remain dimensionally stable.
[0021] FIG. 4B shows a side view of the preferred barrel clamp
assembly 200. Saddle clamp structure 230 comprises two
semi-circular shaped bands 232 with gusseted bolt eye extensions
234, which fit over mortar barrel 120 and bolt on both sides of
saddle structure 220. Saddle clamp structure 230 also comprises a
rigid mechanical connection 236, connecting the two saddle clamp
bands 232, in order to assist in holding the alignment of inertial
isolation and alignment assembly 100 constant. Rigid mechanical
connection 236 can also function as a handle. The entire saddle
clamp structure 230 is preferably machined from a solid piece of
bar stock (such as 4340 steel, for example) to provide uniform
strength and stress distribution throughout the structure. Saddle
clamp structure 230 can also be manufactured from aluminum,
titanium, plastic, composite, or other materials able to withstand
the forces exerted by a particular mortar weapon, and temperature
rise of the mortar barrel experienced during firing. Rigid
mechanical connection 236 and saddle clamp bands 232 of the saddle
clamp structure 230 can be three separate pieces bolted together,
as long as the assembly maintains rigidity.
[0022] FIG. 5A shows a front view of the preferred cage assembly
300. The cage assembly 300 comprises side plates 320, base
structure 330, linear bearing rails 340, shock isolators 350, and
shock dampers 360. Base structure 330 comprises two side members
332, which are bolted to a base member 334 to form a u-shaped shelf
for mounting pointing device 310. Side plates 320 are fastened to
shock isolators 350. Shock isolators 350 are also fastened to side
members 332 of base structure 330. Base structure 330, shock
isolators 350, and side plates 320 form an open-ended box for
encasing pointing device 310. Linear bearing rails 340 are fastened
to side plates 320, and shock dampers 360 are fastened to the front
ends of linear bearing rails 340. Pointing device 310 is bolted
onto base member 334 of base plate 330.
[0023] Shock isolators 350 reduce the parallel and cross-axis
firing shock on the pointing device during a firing event. The
quantity and type of shock isolators 350 used is determined by the
firing shock response spectrum from a particular mortar weapon and
the spectral frequencies and magnitudes of attenuation required by
the isolated mass. Shock isolators 350 are axially aligned with the
center-of-mass of pointing device 310.
[0024] Shock dampers 360 are placed on the front ends of linear
bearing rails 340. Shock dampers 360 provide reduced g-loads on the
suspended pointing device cage assembly 300 as it returns to its
rest position after a firing event. Shock dampers 360 may consist
of air or hydraulic pistons. Shock dampers 360 may alternatively
consist of springs or rubber material.
[0025] FIG. 5B is a side view of the preferred cage assembly 300.
Fasteners 322 connect side plates 320 to linear bearing rails 340.
The fasteners 322 are preferably cap head socket screws, but are
not limited to this type of fastener. Although FIG. 5B shows eight
fasteners 322 attaching each of the linear bearing rails 340 to
each of the side plates 320, this invention is not limited to eight
fasteners, and other numbers of fasteners may be used.
[0026] The length of linear bearing rails 340 is determined by the
maximum amount of linear travel expected by the mortar barrel 120
during a firing event. In the case of the 120 mm mortar weapon, the
typical travel distance required to seat the base plate in soft
soil is approximately 12 inches, therefore the length of guide
rails for this application would be approximately 20 inches.
[0027] FIG. 6 depicts the inertial isolation and alignment assembly
100 mounted on the underside of mortar barrel 120 while the mortar
weapon is at rest prior to the initial firing. The initial
installation of inertial isolation and alignment assembly 100 is
accomplished by bolting saddle clamp structure 230 to saddle
structure 220 around mortar barrel 120 using saddle clamp bolts
240. Saddle clamp bolts 240 are tightened to a predetermined torque
limit, such as 95 ft-lbs. for the 120 mm mortar weapon, in a
sequential pattern at 10 ft-lb. increments. Following proper
installation of barrel clamp assembly 200 around mortar barrel 120,
cage assembly 300 is installed by aligning linear bearing rails 340
with bearing rail followers 210, and sliding cage assembly 300
toward the base plate until it is resting on shock dampers 360, as
shown in FIG. 6. This is the ready-to-fire position.
[0028] FIG. 7 depicts the extended position of the inertial
isolation and alignment assembly 100. During a firing event, mortar
barrel 120 recoils toward the base plate, causing barrel clamp
assembly 200 to slide along linear bearing rails 340 of the
inertial isolation and alignment assembly 100. At the end of the
firing event, mortar barrel 120 comes to a stop, leaving cage
assembly 300 suspended on linear bearing rails 340 at a point equal
to the distance the mortar barrel traveled during firing, as shown
in FIG. 7. This is the extended position. The force of gravity then
causes cage assembly 300 to slide down toward the base plate, and
come to rest on the shock dampers 360 to the ready-to-fire position
depicted in FIG. 6. This operation is repeated as many times as is
required by the firing of the mortar weapon.
[0029] As described above, cage assembly 300 is quickly installed
by aligning linear bearing rails 340 with bearing rail followers
210 and sliding cage assembly 300 to the ready-to-fire position
where it is resting on shock dampers 360. For the quick disconnect,
the process is simply reversed. Cage assembly 300 is removed by
sliding it from the ready-to-fire position beyond the extended
position, until linear bearing rails 340 become free of bearing
rail followers 210.
[0030] Although the invention has been described in detail with
particular reference to a preferred embodiment, other embodiments
can achieve the same results. Variations and modifications of the
present invention will be obvious to those skilled in the art and
it is intended to cover in the appended claims all such
modifications and equivalents. The entire disclosures of all
references, applications, patents, and publications cited above,
are hereby incorporated by reference.
* * * * *