GB2096287A

GB2096287A - Launch vehicle constraining

Info

Publication number: GB2096287A
Application number: GB8209824A
Authority: GB
Original assignee: British Aerospace PLC
Current assignee: BAE Systems PLC
Priority date: 1981-04-04
Filing date: 1982-04-02
Publication date: 1982-10-13

Abstract

Constraining apparatus for holding a vertically launched rocket vehicle in an upright position includes upper and lower jaws 9, 5 which grip a lug 10 on the vehicle, and are vertically adjustable with respect to a rocking member 7 and a temporarily fixed member 1, respectively, by shims, such that a desired clamping force is obtained irrespective of variations in lug position due to build tolerances. The members 1, 7 and their associated jaws are urged together by a geometric lock 11. The force exerted by the lock is determined by replacing it with a jack and load measuring device, extending the jack until the desired force is measured, and re-inserting the lock with adjustment of the jaws 5, 9 as necessary. <IMAGE>

Description

SPECIFICATION Launch vehicle constraining means This invention relates to constraining means for holding vertically launched flight vehicles, for example those rocket vehicles used to carry spacecraft on the first part of a mission, in an upright position both during preparation and also during initial running of the engines until sufficient thrust has been achieved to effect successful liftoff.

According to one aspect of the present invention, such constraining means include a temporarily fixed structural member, a fixed but adjustable lower jaw member carried by the structural member, adjusting means for adjusting the height of the jaw member with reference to the structural member, a movable but adjustable upper jaw member carried by a rocking member itself pivotally mounted on the structural member, adjusting means for adjusting the height of the upper jaw member with reference to the rocking member, the jaw members being arranged to clamp a region of the vehicle, and urging means coupled between the rocking member and the structural member to temporarily urge the upper jaw member toward the clamping position.

Preferably, the urging means includes a geometric lock arrangement which in a rigid locked condition is sized to provide a predetermined loading in the rocking member and hence a predetermined clamping force on the clamped region of the vehicle, and which in an unlocked position releases the predetermined loading and allows the upper jaw member to be urged away from the lower jaw member.

By this arrangement the setting up of the constraining means to provide the predetermined clamping force is facilitated. It is found that, due tq build tolerances, that region of the vehicle to be clamped may vary in its exact location along the length of the vehicle, so that to accurately mount the vehicle in its upright position at a desired height the lower jaw member must be adjusted vertically; naturally this affects the distance between the jaw members and hence the predetermined clamping load exerted. The upper jaw member must accordingly be vertically adjusted. By the presently described arrangement, any adjustment of the height of the lower jaw member to suit a particular vehicle can be effected by shims, and any corresponding adjustment of the upper jaw member can be similarly effected.

Conveniently and simply, such shim adjustment is effected by merely taking a shim from an adjusting position on one jaw and placing it in an adjusting position on the other.

According to a further aspect of the invention, a method ot adjusting such constraining means includes the not necessarily sequential steps of: temporarily fixing the structural member, positioning a dummy region of the vehicle at a desired height by adjusting the lower jaw member with reference to the structural member, replacing the urging means with jack means and load measuring means, clamping said dummy region between the lower and upper jaw members by extending the jack means until a desired clamping load is measured and the distance between the rocking member and the structural member is greater than that dictated by the urging means when in its rigid locked condition, reducing said distance to that dictated by the locked urging means by effecting adjustment of the upper and lower jaw members whilst maintaining the desired clamping load, replacing the jack means and load measuring means with the urging means, and, with said dummy region removed, adjusting the upper and lower jaws identically to suit when the actual height of an actual region of the vehicle to be clamped is known.

Preferably, where the jaw member adjustment is by means of shims, said identical adjustment of the upper and lower jaws is by moving a shim or shims from one jaw to the other.

One embodiment of the invention is now described by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevation of one of four constraining units which in use are equally spaced around a vertical axis with which the longitudinal axis of the vehicle is aligned.

Figure 2 illustrates an enlarged view of the region of box II of Figure 1, and Figure 3 illustrates a similar view to that of Figure 2 but with the apparatus installed to facilitate setting up.

Referring to Figure 1, a constraining unit includes a structural member 1 which for the purposes of the present description is fixed in the support position shown, but can be swung about a horizontal pivot axis 2 by means of a jack 3 away to the right as drawn to clear the vehicle, not shown. A geometric lock arrangement 4 rigidly holds the constraining unit in the support position.

Referring now to Figure 2 additionally to Figure 1, the structural member 1 carries a lower jaw 5 which is adjustable in height with respect to the member 1 by the insertion or removal of shims 6 at a region A between the jaw and the member 1.

The member 1 also carries a rocking member 7, which pivots about an axis 8 parallel to the axis 2.

One end of the rocking member 7 carries an upper jaw 9 which is adjustable with respect to the rocking member by the removal or insertion of shims 6 at a region B between the upper jaw and the rocking member. A shim associated with one jaw can be removed and inserted for association with the other. The jaws 5 and 9 are such to clamp between them a lug 10 being part of the vehicle.

There is one lug for each constraining unit. As before discussed, each lug 10 may deviate from a nominal position, that is to say its position may vary along the length of the vehicle, due to build tolerances. It follows that the position of the lug 10 varies with reference to its associated constraining unit, hence the lower jaw 5 is adjustable in height at A by means of shims 6 to allow for this. As also described the upper jaw 9 is similarly adjustable at B to maintain a desired predetermined clamping load on the lug 1 0.

The structural member 1 also carries urging means in the form of a geometric lock 11 which comprises a first member 1 2 pivoted to that end of the rocking member 7 remote from the upper jaw 9 and to a second member 13 which itself is pivoted directly to the structural member.

The geometric lock members 12 and 1 3 are chosen to be of such a length that when aligned with one another in a locked, rigid condition as drawn, their combined length is such to urge the rocking member 7 so that the jaws exert a desired clamping force on the lug 10, assuming correct setting up. The member 12 is designed to be compressible but at a certain limit of compression to act as a rigid strut; it acts as a rigid strut in the rigid locked condition.

A jack 14 is provided to break the geometric lock at a certain stage in the lift-off sequence by tending to draw the member 1 3 in a clockwise direction as drawn about its pivot on the structural member 1. In this circumstance, the clamping force of the jaws decays since the preload (i.e.

distortion) in the rocking member 7 is removed but a residual clamping force is provided by a spring assembly 1 5 included in and tending to extend the geometric lock member 12.

In use the constraining unit is first set up to provide the predetermined clamping force for a nominal position of the lug 10. When the actual position of the lug 10 on a particular vehicle is known, then the shims 6, if necessary, are moved between the regions A and B to allow for any deviation of the lug from a nominal position without altering the predetermined clamping force.

The initial setting up for a nominal lug position is described as follows with reference to figure 3.

A dummy lug 10 is located in the nominal vertical position by means of the lower jaw 5 adjusted for height by the insertion or removal of shims 6 at A.

The first member 12 of the geometric lock is replaced by a load cell 16 and a hydraulic jack 17 lying in tandem. With the dummy lug 10 in the nominal position, the jack 1 7 is extended to clamp the lug 10 between the upper and lower jaws 5 and 9 respectively until the desired clamping load is indicated by the load cell 1 6 readout. The dimension X is then measured, the arrangement being that the measured dimension X is always greater than the length of a standard first member 12. The dimension X is then reduced, by placing shims 6 at B, to the exact length of the standard first member 12 whilst maintaining the desired clamping load. The load cell 1 6 and the hydraulic jack 1 7 are removed and replaced by the first member 12. As before stated, any deviation of a position of the lug 10 from the nominal position in an actual vehicle to be launched is accommodated by moving shims 6 of identical thickness between the regions A and B. The predetermined clamping load is unaffected.

Claims

1. Constraining means for holding vertically launched flight vehicles in an upright position, including a temporarily fixed structural member, a fixed but adjustable lower jaw member carried by the structural member, adjusting means for adjusting the height of the jaw member with reference to the structural member, a movable but adjustable upper jaw member carried by a rocking member itself pivotally mounted on the structural member, adjusting means for adjusting the height of the upper jaw member with reference to the rocking member, the jaw members being arranged to clamp a region owt the vehicle, and urging means coupled between the rocking member and the structural member to temporarily urge the upper jaw member toward the clamping position.

2. Constraining means, according to Claim 1, wherein the urging means includes a geometric lock arrangement which in a rigid locked condition is sized to provide a predetermined loading in the rocking member and hence a predetermined clamping force on the clamped region of the vehicle, and which in an unlocked position releases the predetermined loading and allows the upper jaw member to be urged away from the lower jaw member.

3. Constraining means, according to Claim 1 or Claim 2, wherein the adjusting means for the lower jaw member and the upper jaw member are such to allow identical adjustment of each jaw member.

4. Constraining means, according to Claim 3, wherein the adjusting means include at least one shim which can be moved from one jaw member to the other jaw member,

5. A method of adjusting the constraining means of Claim 2 including the not necessarily sequential steps of- temporarily fixing the structural member, positioning a dummy region of the vehicle at a desired height by adjusting the lower jaw member with reference to the structural member, replacing the urging means with jack means and load measuring means, clamping said dummy region between the lower and upper jaw members by extending the jack means until a desired clamping load is measured and the distance between the rocking member and the structural member is greater than that dictated by the urging means when in its rigid locked condition, reducing said distance to that dictated by the locked urging means by effecting adjustment of the upper and lower jaw members whilst maintaining the desired clamping load, replacing the jack means and load measuring means with the urging means, and, with said dummy region removed, adjusting the upper and lower jaws identically to suit when the actual height of an actual region of the vehicle to be clamped is known.

6. A method of adjustment, according to Claim 5, where the jaw member adjustment is by means of shims, wherein said identical adjustment of the upper and lower jaws is by moving a shim or shims from one jaw to the other.

7. Constraining means for holding vertically launched flight vehicles in an upright position substantially as described with reference to Figures 1 and 2 of the accompanying drawings.