GB2049079A - Snubber assembly - Google Patents

Abstract

A snubber assembly includes an axially elongated member 10 or 65 which is axially-movable, and a rotary structure 18 or 77 coupled to the member to be rotated in response to axial movement of the member. Either the member or the rotary structure is in the form of a rod of polygonal cross- section twisted along its length. Snubber means 24 in the form of a multi-disc brake unit is coupled to the rotary structure for frictionally resisting rotation of the structure and axial movement of the member and in such manner as to increase the frictional resistance as axial loading exerted by the member increases. In the embodiment of Figure 2 the rod 10 forming the member is received within structure 18 which is in the form of a torque tube rotatable in a housing 14. The tube is coupled to the disc brake unit by a stem 26. The disc brake unit 24 may operate in one or both directions of axial movement of rod 10 (c.f. Figures 5 6). In the embodiment of Figure 7, the rotary structure 77 is the twisted rod received in a polygonal section piston rod 65 forming the member. <IMAGE>

Description

SPECIFICATION Snubber assembly This invention relates generally to snubbers, and more particularly concerns a compact mechanism that controls rate of movement of apparatus or equipment in retract, extend, or both retract and extend modes.

Prior snubbing devices are exemplified by U.S.

Patents 1,700,558; 1,933,768; 1,808,837; 2,411,481; 2,969,560; 3,990,542; 3,951,238 and 3,765,053. None of these patents embodies advantageous combinations and sub combinations of features and advantages of the present load-sensitive, compact lightweight snubber mechanism and wherein a brake such as disc type brake is located within a tubular housing that contains a tube and a twisted rod or shaft, these being relatively rotatable in response to their relative axial displacement to effect energization of the disc brake. As will appear, as linear loading increases, the snubbing action of the disc brake unit increases.

Basically, the invention is embodied in a combination that includes: (a) an axially elongated member that is axially movable, (b) rotary structure coupled to that member to be rotated in response to such axial movement of the member, one of the member and structure having a load transmitting shoulder extending along a spiral path about and along the member axis, (c) and snubber means coupled to the rotary structure for frictionally resisting the structure rotation and the member axial movement and in such manner as to increase said frictional resistance as axial loading exerted by the member increases.

As will appear, the axial movement of the member relative to the rotary structure not only serves to rotate such structure including rotary discs associated therewith, but also exerts axial force to load the disc brake unit that includes the rotor discs and also stator discs, to provide the axial load sensitive snubbing action. The stator discs are associated with a housing for the brake unit and for the member and rotary structure, as will be seen, whereby a very compact, load sensitive assembly is provided.

These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following description and drawings, in which: Figure 1 is a side elevation showing one application of the invention, Figure 2 is a side elevation, in section, showing a snubber incorporating the invention, Figure 3 is an enlarged vertical section taken on lines 3-3 of Figure 2, Figure 4 is an enlarged vertical section taken on lines 4-4 of Figure 2, Figure 5 is an axial vertical section taken on lines 5-5 of Figure 4, Figure 6 is a view like Figure 5, but showing a modification, Figure 7 is a view like Figure 2, showing a modified form of the invention, and, Figure 8 is a section on lines 8-8 of Figure 7.

Referring first to Figure 2, an axially elongated member is provided to be relatively axially movable. In the example shown, the member comprises a linearly elongated rod 10 having a polygonal cross-section, the rod being twisteci along its length. Typically, the rod may have a generally square cross-section in planes normal to the rod axis 11 , so that flute-like edges 12, and flats 13 extend in spiral configuration along the rod length, the edges 12 having the same radii from the axis 11. Rod 10 extends partly within a tubular housing 14, and partly projecting endwise therefrom. A fitting 1 5 is attached as by pin 1 6 to a reduced diameter portion 1 Oa of the projecting end of the rod, to transfer axial loading to or from same.A similar fitting 1 7 may be attached to the remote end 1 4b of the housing. Fittings 1 5 and 1 7 may be employed to block rotation of the rod and housing, about axis 11.

Rotary structure is coupled to the member, such as rod 10, to relatively rotate in response to axial movement of the rod. In the illustrated example such structure takes the form of a torque tube 1 8 located coaxially within the housing 14, and axially receiving a portion of the twisted rod in such manner that the rod is axially movable relative to the torque tube, and the tube is rotatable about axis 11 relative to the rod and the housing. Coupling of the rod to the tube is provided by a coupler bearing 19, the bore 1 9a of which is polygonal to slidably interfit the rod cross-section, as for example is shown in Figure 3.

The coupler bearing 1 9 has spline connection at 20 to the torque tube so as to rotate the latter as the rod moves endwise to rotate the coupler. The end 1 9b of the coupler has thrust bearing engagement with a retainer or cap 21 threadably attached to the end of the housing. Tube 1 8 is slidably received in the bore 1 4a of the housing to rotate therein. A guide piston 22 is pin connected at 23 to the inner, reduced diameter end 1 Ob of the rod 10, to slidably guide on the bore 1 8a of the torque tube, thereby centering the rod, coaxially with the tube and housing.

In accordance with an important aspect of the invention, snubber means is coupled to the rotary structure for frictionally resisting rotation of such structure and rod member axial movement, all in such manner as to increase such frictional resistance as axial loading exerted by the rod member increases. In this regard, the snubber means may typically and advantageously comprise a disc brake unit contained by tubular housing structure such as housing 14.

As illustrated in Figures 2, 4 and 5, the disc brake unit indicated generally at 24 has at least one rotor or disc 25 and typically multiple rotors 25, operatively connected to the rotary structure such as tube 18, to be rotated by the latter. Such operative coupling may be provided by an axially elongated stem 26 pinned at 27 to the torque tube 18, the stem having a polygonal (square) cross-section (see Figure 4) to interfit the matching polygonal bores 28 of the rotors or discs 25.

The disc brake unit illustrated also includes at least one stator 30, and typically multiple stators 30, operatively connected to the housing structure 14 so as not to rotate, but at the same time accommodating axial movement of the stators.

They also project between or adjacent the multiple rotors (discs) to have face-to-face sliding frictional braking engagement therewith at locations 31. In this regard, the stators are shown to include brake pads 30a of non-metallic material, rigidly bonded to the stator discs 30b. If desired, the brake pads may be bonded to the rotor discs, instead of to the stators.

The stators have guide tangs 30c which project radially outwardly into axially extending grooves 33 formed in the housing wall, as shown. Such grooves allow axial travel of the stators, but block their rotation relative to the housing, about axis 11. The stator discs are annular and form openings 30d which loosely pass the stem 26.

A plug 34, which may be integral with connector 17, is threaded into the housing end 14b at 35, and provides an end face 36 to receive axial loading exerted by the tube 1 8 (in the direction of arrow 36a in Figure 5), and via the disc brake unit. Such axial loading develops due to attempted endward or axial travel of the rod 10 rightwardly in Figure 2, for example, to rotate the tube 18. As a result, the endwise loading is exerted axially on the stack of rotors and stators to squeeze them between the torque tube end face 37, and the plug end face 36, seen in Figure 5.

Braking torque thus developed is transmitted from the rotors 25 to the tube 18, resisting tube rotation and thereby snubbing axial travel of rod 10 in one axial direction, i.e. to the right in Figure 2.

Figure 1 shows one unusually advantageous application of the snubber assembly to provide resistance to opening of a compartment closure, as for example closure 40 to a luggage storage compartment 41 on an aircraft. The snubber assembly 42, like that shown in Figure 2, is above and outside the compartment. Connector 1 7 is pivotally supported at 43, and connector 15 is pivotally connected at 44 to arm 45 of bell crank 46. The latter is pivoted at 47 to frame 48, so that arm 45 projects through an opening 49 in the compartment. Arm 50 of the crank 46 has lost motion tongue and groove connection at 51 to arm 52 which is pivotally connected at 53 to the frame. The closure 40 is connected to arm 52, to pivot at 53.As the closure is swung downwardly in the direction of arrow 54, the linkage causes the rod 10 of the snubber assembly to move in the direction of arrow 55, producing snubbing action to resist but not prevent opening of the closure.

This prevents sudden opening of the luggage compartment, and possible injury to passengers from falling luggage. If desired, an additional damper 57 may be connected between arm 50 and pivot 58 on the frame. A suitable detent 59 may hold the closure lip 60 in up or closed position.

Figure 6 shows a modification of Figure 5 allowing additional snubbing action in the opposite (i.e. leftward) direction of rod 10 axial displacement. For that purpose, one end stator 300 may project radially inwardly into an annular groove 62 in the stem 26. Also, stops 61 on the housing project into proximity to the tangs 30c of opposite end stator 300a. As a result, when the rod 10 moves in that opposite direction, stator 300 acts as a plate urged to the left by the tube 1 8 to clamp the rotor-stator combination between that plate and the stops 61, providing braking and consequential snubbing action.

In the modified form of the invention shown in Figures 7 and 8, the axially-elongated member that is axially movable takes the form of piston rod 65, which has a polygonal (as for example square) external cross section. A rod end assembly 66 is attached at 67 to one end of the rod 65. A shaft bearing 68 attached at 69 to the opposite end of the rod includes an annular periphery at 68a axially slidable in the tubular bore 70 of body or housing 71. The piston rod 65 itself is axially slidable in the bore 72 of rod end bearing 73 which is attached at 74 to the body 71. Bore 72 is polygonal to match the polygonal periphery of the rod 65. Accordingly, torque exerted on the rod 65 during its axial displacement, and via the shaft bearing 68, is removed from the rod via bearing 73 and transferred to body 71.Ultimately, such torque is exerted on the head end assembly 75 attached at 76 to the body enlargement 71 a.

In Figures 7 and 8 the rotary structure coupled to the rod 65 via the bearing 68, and which exerts torque on the rod via that bearing, comprises a linearly elongated shaft 77 having a polygonal cross-section, the shaft twisted along its length and extending within the hollow rod as shown.

The twisted shaft also extends through the annular bearing 68 and these two elements have polygonal sliding interfit, whereby as the rod 65 is moved axially relative to body 71 and shaft 77, the latter is rotated.

Also shown in Figure 7 is the snubber means in the form of the disc brake unit 79 received within the bore 80 of the body enlargement 71 a. The unit 79 includes multiple coaxial rotor discs 81 and stator discs 82, the latter typically having brake lining on their axial faces frictionally to engage the faces of the rotor discs. The rotor discs are coupled to stem 83 formed as an integral end extension of the twisted shaft, to be rotated as the shaft rotates. The couplings of the rotors to the stem may be as described above. The stator discs are coupled to the body enlargement 71 a, and such coupling may be afforded by square outline stators working in the square bore 80 of the body enlargement. A disc retaining collar 84 is also attached to the stem, as by dowel 85, and has a hub 84a engaging one stator disc. A retaining plate 86 retains the rotary collar axially, and is suitably attached to the body 71.

Accordingly, as the rod 65 moves axially toward the snubber means in Figure 7, the twisted shaft 77 and rotor discs are rotated, and axial force is exerted via the twisted shaft and the retainer collar 84 to axially frictionally interengage the rotor and stator discs to brake axial movement of the rod.

Claims (20)

1. In a snubber assembly, the combination comprising: (a) an axially elongated member that is axially movable, (b) rotary structure coupled to said member to be rotated in response to said axial movement of the member, one of said niember and structure having a load transmitting shoulder extending along a spiral path about and along said member axis, (c) and snubber means coupled to said rotary structure for frictionally resisting said structure rotation and said member axial movement and in such manner as to increase said frictional resistance as axial loading exerted by said member increases.

2. The combination of Claim 1 wherein said member comprises a linearly elongated rod having a polygonaiAcross-section, the rod twisted along its length to define said shoulder.

3. The combination of Claim 2 wherein said structure includes a torque tube within which said twisted rod extends and relative to which the rod is axially linearly movable.

4. The combination as claimed in any one of the preceding claims wherein said snubber means comprises a disc brake unit, and a tubular housing containing said unit said member and said rotary structure and relative to which said member is axially movable.

5. The combination of Claim 3 wherein said snubber means comprises a disc brake unit and a tubular housing containing said unit, said rod, and said rotary structure which includes said torque tube.

6. The combination as claimed in any one of Claims 1 to 3 wherein said snubber means comprises a disc brake unit having at least one rotor operatively connected to said rotary structure to be rotated thereby, and at least one stator to frictionally engage said rotor and relative to which the rotor is rotatable, there being housing means for said unit and said rotary structure, the stator operatively connected to the housing means.

7. The combination of Claim 6 wherein the rotor is also axially movable to exert increasing axial force on the stator in response to axial displacement of the member and rotary structure.

8. The combination as claimed in either Claim 6 or Claim 7 wherein said unit includes multiple of said rotors operatively connected to the rotary structure, and multiple of said stators located between the rotors to have face-to-face engagement therewith.

9. The combination as claimed in either Claim 6 or Claim 7 wherein the housing means has cylindrical configuration, and the member projects from the cylindrical housing means, there being axially spaced end connections on said member and on said housing means.

10. The combination as claimed in any one of Claims 3 to 9 including a coupler slidably interfitting the polygonal cross-section rod, the coupler attached-to the torque tube to rotate the tube as the coupler is rotated by the rod.

11. The combination as claimed in any one of Claims 7 to 10 including a compartment having a closure movable to open and close the compartment, said snubber assembly operatively attached to the closure to resist said movement thereof.

12. The combination of Claim 11 including a linkage interconnecting the closure to the snubber assembly.

13. The combination as claimed in any one of Claims 6 to 12 2 wherein the snubber means includes clamping shoulders between which the rotor and stator are clamped together to develop snubbing force in response to axial travel of said member in either axial direction.

14. In a snubber assembly, the combination comprising: (a) an axially elongated first member, (b) a second member extending about the first member, (c) means coupling the members to rotate one of the members and to transmit axial loading thereto in response to axial movement of the other member relative to the one member, (d) a disc brake unit having frictionally interengageable stator means and rotor means, (e) means coupling said one member to the rotor means to rotate therewith and to transmit axial loading from said one member to the rotor means, (f) and means blocking rotation of the stator means, (g) whereby rotation of the one member and axial loading transmitted by said one member to the rotor means all in response to said relative axial movement of the other member produces frictional interengagement of the rotated rotor means and the non-rotary stator means to snub said member relative axial movement.

1 5. The combination of Claim 1 wherein said one member comprises a linearly elongated shaft having a polygonal cross section, the shaft twisted along its length and coupled to said other member to be rotated in response to relative axial movement of said members.

1 6. The combination of Claim 1 5 including an axially elongated tubular body in which the other member extends for axial movement relative thereto, the other member coupled to said body to transfer torque thereto in response to said relative axial movement of said members.

1 7. The combination of Claim 1 6 including a bearing coupling the other member to said body, the other member having a polygonal external cross-section, and the bearing having a matching polygonal bore in which the other member is relatively slidable.

1 8. The combination as claimed in either Claim 16 or Claim 17 wherein said snubber means comprises a disc brake unit, the unit received within the body.

19. The combination of Claim 18 wherein said disc brake unit has at least one rotor operatively connected to said twisted shaft to be rotated thereby, and at least one stator to frictionally engage said rotor and relative to which the rotor is rotatable, the stator operatively connected to the body.

20. In a snubbing assembly, (a) a tube and a twisted shaft extending within the tube, both extending longitudinally and being relatively longitudinally movable, one rotatable relative to the other in response to said relative longitudinal movement, and (b) a disc brake including relatively rotatably rotor and stator elements which are slidably interengaged, the rotor elements coupled to said one of said shaft and tube to be rotated thereby to frictionally slide against the stator element and produce braking force tending to resist said relative longitudinal movement.