Collision avoidance guidance device
By designing an anti-collision guidance device at the aircraft cargo door, and utilizing the ramp surface transition section and rotatable hinge assembly, the problem of easy damage to the transfer rollers was solved, achieving reliable guidance and space saving for the container.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- COMMERCIAL AIRCRAFT CORP OF CHINA LTD
- Filing Date
- 2024-04-18
- Publication Date
- 2026-06-26
Smart Images

Figure CN118323425B_ABST
Abstract
Description
Technical Field
[0001] This invention relates generally to the technical field of collision protection for aircraft cargo systems, and more specifically, to a collision guidance device for aircraft cargo doors. Background Technology
[0002] In existing aircraft cargo systems, the cargo hold doors are equipped with door extensions, which are used as anti-collision guidance structures to guide containers in and out of the doors. However, in actual use, these extensions are often damaged due to improper operation.
[0003] In some anti-collision guidance structures, multiple transfer rollers are installed on a flat plate on its extension section to guide the container. When using this type of guidance structure, loading and unloading workers must visually ensure that the ground platform vehicle platform is aligned with the top of the transfer rollers to reliably prevent damage to the transfer rollers. However, due to the very small radius of the transfer rollers, visually ensuring alignment between the ground platform vehicle platform and the top of the transfer rollers is not so easy. In actual operation, it often happens that the ground platform vehicle platform is lower than the center horizontal line of the transfer rollers. Once this happens, the transfer rollers and roller supports are easily damaged by the container as it is pushed through the hatch, thus hindering the loading and unloading operation.
[0004] Based on existing cargo door guidance structures and considering aircraft design requirements, we aim to provide a collision avoidance guidance structure for aircraft cargo systems that guides containers in and out of cargo doors during loading and unloading, preventing damage to the transfer rollers on the structure. Furthermore, we also desire a collision avoidance guidance structure that occupies as little space as possible when retracted. Summary of the Invention
[0005] To overcome the shortcomings of the prior art, the present invention provides a collision avoidance guidance device for an aircraft cargo door, comprising: a base plate having an upper surface and a lower surface, as well as a rear edge and a front edge; and a rolling transfer assembly mounted on the upper surface of the base plate, wherein the base plate of the collision avoidance guidance device has a transition portion disposed at the front edge of the collision avoidance guidance device, the transition portion having a ramp surface having a front edge relatively far from the rolling transfer assembly and a rear edge relatively close to the rolling transfer assembly, wherein when the base plate of the collision avoidance guidance device is placed horizontally, the height position of the front edge is lower than the height position of the rear edge, and the height position of the rear edge of the ramp surface is higher than the upper surface of the base plate but not higher than the top of the rolling transfer assembly.
[0006] By employing the anti-collision guiding device according to the present invention, the transition portion at the front edge of the base plate can reliably guide the container onto the top of the rolling element, preventing the container from impacting the rolling element from a horizontal direction and reducing the possibility of damage to the rolling element.
[0007] According to one aspect of the invention, the rolling transmission assembly includes a rolling element and a support rotatably holding the rolling element, the rolling element being held by the support on the upper surface of a base plate, wherein when the base plate of the anti-collision guide device is placed horizontally, the height position of the rear edge of the ramp surface is lower than the height position of the top of the rolling element.
[0008] According to one aspect of the invention, the anti-collision guiding device further includes a guide rail assembly having a guide surface, the guide rail assembly being disposed at opposite first and / or second side edges of the base plate, and the guide rail assembly having an open state and a closed state. When the guide rail assembly is in the open state, the guide surface is vertical to the upper surface of the base plate; when the guide rail assembly is in the closed state, the guide surface moves away from the vertical position and closer to the upper surface of the base plate. The anti-collision guiding device is provided with an openable and closable guide rail assembly. When the anti-collision guiding device is retracted and not in use, the guide rail assembly can be closed to reduce the height of the guide rail assembly protruding from the base plate. The guide surface in such a guide rail assembly can also be made longer accordingly, thereby ensuring the reliability of side guidance.
[0009] According to another aspect of the invention, the guide rail assembly includes: a guide rail base fixed to a base plate; a guide rail having a guiding surface; and a pivot shaft through which the guide rail is rotatably mounted to the guide rail base. Advantageously, the height of the guide rail when open is higher than the height of the rolling transmission assembly, and the height when closed is lower than the height of the rolling transmission assembly.
[0010] According to another aspect of the invention, the guide rail assembly further includes a locking device for locking the guide rail in a closed state.
[0011] According to another aspect of the invention, the anti-collision guidance device further includes a hinge assembly disposed at the rear edge of the base plate, the hinge assembly being configured to pivotally connect to the base plate, the hinge assembly including: a hinge connecting seat connected to the base plate; a hinge support seat fixable to a fixed plate in the aircraft cargo hold; and a hinge pivot portion through which the hinge support seat is rotatably connected to the hinge connecting seat.
[0012] According to another aspect of the invention, the hinge assembly further includes a hinge locking portion configured to lock the hinge connector and the hinge support at a predetermined angle. The hinge locking portion holds the anti-collision guide in its retracted position.
[0013] According to another aspect of the invention, the height of the leading edge of the ramp surface is not lower than the height of the upper surface of the base plate, and the angle of inclination of the ramp surface of the transition portion relative to the horizontal plane is between 15° and 35°.
[0014] According to another aspect of the invention, the transition portion further includes a leading edge wall and an attachment wall, as well as a recess located on the opposite side of the ramp surface, wherein the attachment wall is for attachment to the bottom plate, and a support pad is embedded in the recess. The side edges of the anti-collision guide device are relatively more susceptible to impact during cargo loading and unloading; therefore, embedding a support pad in the recess effectively enhances the strength of the side edges of the anti-collision guide device, reducing the possibility of deformation or damage to the transition portion.
[0015] According to another aspect of the invention, the anti-collision guidance device further includes a plurality of support pads disposed on the lower surface of the base plate. Attached Figure Description
[0016] To gain a more complete understanding of the invention, reference can be made to the following description of exemplary embodiments taken in conjunction with the accompanying drawings, in which:
[0017] Figure 1 A perspective view of a collision avoidance guide device for an aircraft cargo door according to a preferred embodiment of the present invention is shown.
[0018] Figure 2 Another perspective view of a collision avoidance guide device for an aircraft cargo door according to a preferred embodiment of the present invention is shown.
[0019] Figure 3 A perspective view of a guide rail assembly of a collision avoidance guiding device according to a preferred embodiment of the present invention is shown, wherein the guide rail assembly is in an open state.
[0020] Figure 4 Another perspective view of the guide rail assembly of the anti-collision guide device according to a preferred embodiment of the present invention is shown, wherein the guide rail assembly is in a closed state.
[0021] Figure 5 A perspective view of a hinge assembly of a collision avoidance guidance device according to a preferred embodiment of the present invention is shown, wherein the hinge assembly is in an open state.
[0022] Figure 6 Another perspective view of the hinge assembly of the anti-collision guidance device according to a preferred embodiment of the present invention is shown, wherein the hinge assembly is in a folded state.
[0023] Figure 7 A side view of a collision avoidance guidance device according to a preferred embodiment of the present invention is shown.
[0024] List of reference numerals
[0025] 100 anti-collision guidance device
[0026] 10 base plate
[0027] 11 Upper surface
[0028] 12 Lower Surface
[0029] 13 front edge
[0030] 14 back edge
[0031] 15, 16 side edges
[0032] 17 Window Department
[0033] 20 Transitional Section
[0034] 21 Leading edge wall
[0035] 22 Slope Surface
[0036] 23 attached walls
[0037] 25 concave part
[0038] 30 hinge assembly
[0039] 31 Hinge Connector
[0040] 32 hinge support base
[0041] 33 Hinges and pivots
[0042] 34 Hinge Locking Part
[0043] 35 locking pin
[0044] 36 operating handles
[0045] 37 Pin Compression Spring
[0046] 38 recess
[0047] 50 Rolling Transfer Components
[0048] 51 Rolling Components
[0049] 52 stents
[0050] 60 guide rail assembly
[0051] 61 Guide Rail
[0052] 62 guide rail base
[0053] 63 guide rail spindle
[0054] 64 locking lever
[0055] 65 Torsion Spring
[0056] 66 Tie rod support seat
[0057] 67 socket
[0058] 70 support base
[0059] 71 support pad
[0060] 80 container Detailed Implementation
[0061] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.
[0062] Figure 1 A top perspective view of a collision avoidance guide device 100 for an aircraft cargo door according to a preferred embodiment of the present invention is shown; while Figure 2 It shows Figure 1 The bottom perspective view of the anti-collision guide device 100. The anti-collision guide device 100 is typically installed at the threshold along the entire length of the aircraft cargo door threshold to guide cargo such as containers 80 into and out of the cargo door during aircraft loading and unloading, preventing cargo from colliding with the edge of the cargo door frame and protecting the threshold of the door.
[0063] like Figure 1 As shown, the anti-collision guidance device 100 mainly includes a base plate 10, a hinge assembly 30 for connecting the base plate 10 to the threshold or floor of the cargo hold, a rolling transfer assembly 50 for rolling to guide the movement of cargo, and a guide rail assembly for guiding cargo in and out of the cargo hold door from the side.
[0064] like Figure 1 and Figure 2 As shown, the base plate 10 of the anti-collision guidance device 100 is elongated, and its length corresponds to the sill length of the cargo door. The base plate 10 has... Figure 1 The visible upper surface 11 and Figure 2 The lower surface 12 is visible in the center. The floor plate 10 has opposing front edges 13 and rear edges 14 along its length and opposing side edges 15 and 16 along its short side. Here, "front edge" refers to the side edge of the floor plate 10 that is relatively away from the cargo door when the anti-collision guide device 100 is in the operating position, and "rear edge" refers to the side edge of the floor plate 10 that is relatively close to the cargo door when the anti-collision guide device 100 is in the operating position. "Side edge" is the floor plate edge that connects the front edge and the rear edge.
[0065] like Figure 1As shown, multiple rolling transfer assemblies 50 are mounted on the upper surface 11 of the base plate 10 of the anti-collision guide device 100. Each rolling transfer assembly 50 includes a rolling element 51 and a bracket 52 that rotatably holds the rolling element 51. The bracket 52 is mounted to the upper surface 11 of the base plate 10 by fasteners. One rolling element can be pivotally held on one bracket 52, or multiple rolling elements can be held. Figure 1 In the illustrated embodiment, the rolling elements 61 are cylindrical rollers arranged with their axes parallel. It should be understood that other forms of rolling elements are also feasible. The top positions of the multiple rolling elements 51 on the bottom plate are kept on the same horizontal plane, and the size and number of rolling elements on the bottom plate 10 can be determined according to the size of the bottom plate 10 and the load requirements.
[0066] Specifically, along the front edge 21 of the base plate 10, the anti-collision guide device 100 is provided with a transition portion 20 having a ramp surface 22, the transition portion 20 being arranged to guide the container onto a rolling transfer assembly 50 disposed on the base plate 10. Figure 7 As shown, when the base plate 10 of the anti-collision guide device is in a horizontal position, the ramp surface 22 of the transition section 20 is arranged such that the height of the ramp surface 22 relative to the leading edge of the rolling transmission assembly is lower than the height of the ramp surface 22 relative to the trailing edge of the rolling transmission assembly, that is, the height of the ramp surface 22 relative to the leading edge of the rolling transmission assembly 50 on the base plate 10 is lower than the height of the ramp surface 22 near the trailing edge of the rolling transmission assembly 50. Preferably, the height of the leading edge of the ramp surface 22 is not lower than the height of the upper surface of the base plate 10, while the height of the trailing edge of the ramp surface 22 is higher than the upper surface of the base plate 10 and close to but not higher than the top of the rolling transmission assembly 50. In this way, when the container 80 moves along the ramp surface 22, the bottom of the container 80 is raised by the ramp surface 22, making it easier for the bottom of the container to reach the top of the rolling transmission assembly 50, that is, to reach the top of the rolling transmission assembly 50. Figure 7 On the top of the roller shown.
[0067] Preferably, the inclination height of the ramp surface 22 of the transition section 20 can be determined based on the tolerance height difference of the ground platform vehicle platform. The tolerance height position of the ground platform vehicle platform used for transporting goods into the cargo hold is controlled between the lowest point at the leading edge of the ramp surface 22 of the transition section 20 and the top of the rolling element 51. That is, the surface height position of the ground platform vehicle platform can be maintained between the lowest point of the ramp surface 22 and the top of the rolling element, so that the bottom of the goods can contact the ramp surface 22 and be lifted up along the ramp surface 22 to the top of the rolling element 51. Currently, the tolerance height of conventional ground platform vehicles is 50mm, and correspondingly, the distance between the lowest point at the leading edge of the ramp surface 22 of the transition section 20 and the top of the rolling element 51 is set to be greater than 50mm. On the other hand, as Figure 7As shown, the height of the highest point of the slope surface 22 of the transition section 20 is preferably slightly lower than the top position of the rolling element 51.
[0068] In a preferred embodiment, the slope surface 22 of the transition portion 20 has an inclination angle relative to the horizontal plane that is between 15° and 35°, preferably between 20° and 30°, and more preferably 25°. This inclination angle setting is beneficial for lifting and guiding the container 80 onto the top surface of the rolling element 51.
[0069] like Figure 7 As shown, the transition portion 20 can be formed by stamping a metal sheet. The transition portion 20 includes, from front to back, a leading edge wall 21, a sloping surface 22, and an attachment wall 23. (As shown...) Figure 7 As shown, the vertically extending leading edge wall 21 forms the leading edge of the entire anti-collision guide device 100, and the attachment wall 23 is configured for mounting the base plate 10 via fasteners. In other alternative embodiments, the transition portion 20 may also be integrally formed with the base plate 10, for example, by stamping integrally forming it on the leading edge of the base plate 10. For ease of manufacturing and installation, the transition portion 20 may be formed by splicing multiple independent identical segments along the leading edge of the base plate 10, such as... Figure 1 As shown. Preferably, the transition portion 20 is provided continuously along the entire front edge of the base plate 10. In other alternative embodiments, the segments of the transition portion 20 may be provided at intervals.
[0070] In addition, such as Figure 2 As shown, a support pad 71, for example made of rubber, is also provided between the front edge 13 of the base plate 10 and the front edge wall 21 of the transition portion 20. This support pad 71 is embedded in the recess 25 on the opposite side of the ramp surface 22. In practice, it has been found that impacts are more likely to occur at the side edges of the anti-collision guide device; therefore, in a preferred embodiment, the support pad 71 is only located near the side edges of the anti-collision guide device. Figure 2 As shown, part of the anti-collision guidance device, the transition section 20 of the anti-collision guidance device is separated by two support pads 71 by a distance, which is used to buffer the force between the bottom of the container 80 and the transition section 20 when the container 80 enters the hatch.
[0071] The hinge assembly 30 of the anti-collision guidance device 100 is located at the rear edge 14 of the floor plate 10. The hinge assembly 30 is configured to allow the floor plate 10 to fold or open relative to the cargo hold floor. Figure 1 As shown, the anti-collision guidance device 100 of the preferred embodiment includes two hinge assemblies 30, but it should be understood that if the base plate 10 is long, it may also include a greater number of hinge assemblies 30.
[0072] Figure 5 and Figure 6 Perspective views of the hinge assembly 30 in an open state and a folded state according to a preferred embodiment of the present invention are shown respectively.
[0073] like Figure 5 and Figure 6 As shown, the hinge assembly 30 includes a hinge connector 31, a hinge support 32, a hinge pivot 33, and a hinge locking part 34. On one hand, the hinge assembly 30 is connected to the cargo hold's fixed plate via the hinge support 32 using several fasteners, typically directly fixed to the cargo hold floor. On the other hand, the hinge assembly 30 is connected to the base plate 10 via the hinge connector 31 using fasteners. The hinge support 32 is rotatably connected to the hinge connector 31 via the hinge pivot 33.
[0074] Furthermore, the hinge locking part 34 is configured to lock the hinge connecting seat 31 and the hinge support seat 32 at a set angle, thereby locking the bottom plate 10 of the anti-collision guide device 100 relative to the cargo compartment floor at a set angle. Preferably, the hinge locking part 34 includes a locking pin 35, an operating handle 36, and a pin compression spring 37. The operating handle 36 is mounted on one end of the locking pin 35 for pulling the locking pin 35 to unlock the hinge assembly 30. The locking pin 35 passes through a channel formed in the hinge connecting seat 31 and moves along the channel. In addition, the hinge support seat 32 is provided with a groove or recess 38, such as... Figure 6 As shown, when the hinge support 32 is in a position perpendicular to the hinge connecting seat 31, the other end of the locking pin 35 can be engaged in the recess 38 of the hinge support 32, thus locking the relative rotational position of the hinge support 32 and the hinge connecting seat 31.
[0075] To facilitate user operation of the control handle 36, such as Figure 2 As shown, a window 17 is provided on the base plate 10, and the operating handle 36 is exposed in the window 17. When the base plate 10 of the anti-collision guide device 100 is in a vertical position, the operating handle 36 can be easily operated through the window 17.
[0076] When the hinge assembly 30 rotates to the open position, thus opening the anti-collision guide device 100 to the usable position (i.e., the base plate 10 is in a basically horizontal position), as... Figure 5 As shown, the end of the locking pin 35 is located below the hinge support. As the hinge support rotates, the cam surface on the outer side of the hinge support 32 pushes the end of the locking pin 36 against the axial compression spring 37. When the hinge support 32 rotates to a position where the end of the locking pin 35 aligns with the slot or recess 38, the end of the locking pin 35 engages in the slot or recess, thereby holding the hinge assembly 30 in its folded position. According to a preferred embodiment of the invention, from the open position of the hinge assembly 30 to the folded position of the hinge assembly 30, the hinge connecting seat 31 rotates 90 degrees around the pivot.
[0077] Figure 3and Figure 4 Perspective views of the guide rail assembly 60 of the anti-collision guiding device 100 according to a preferred embodiment of the present invention are shown, wherein the guide rail assembly 60 is in an open state and a closed state, respectively. The guide rail assembly 60 may be disposed at the side edge 15 and / or side edge 16 of the base plate 10.
[0078] Better, such as Figure 3 and Figure 4 As shown, the guide rail assembly 60 includes a guide rail 61 and a guide rail base 62 for fixing to the base plate. The surface of the guide rail 61 preferably forms an arc-shaped guide surface. When the guide rail assembly is in the open state, the guide surface is vertical to the upper surface of the base plate 10, thereby guiding the container moving against it; when the guide rail assembly is in the closed state, the guide surface moves closer to the upper surface of the base plate, preferably, the guide surface becomes parallel to the upper surface 11 of the base plate 10. The guide rail 61 is connected to the guide rail base 62 via a guide rail pivot 63, at which a torsion spring 65 is provided. The torsion of the torsion spring 65 allows the guide rail 61 to be held in the open state.
[0079] Furthermore, the guide rail assembly 60 also includes a locking device for locking the guide rail 61 in a closed state. In a preferred embodiment, the locking device includes a locking support 66 and a locking lever 64 slidably inserted into a through slot in the locking support 66. The end of the guide rail 61 is provided with a socket 67. When the guide rail 61 is folded inward toward the base 62 and rotated to a position abutting the upper surface of the base 62, the end of the locking lever 64 can be inserted into the socket 67, thereby locking the guide rail 61 in the closed state. When it is necessary to open the guide rail 61, simply pull out the locking lever 64. Under the elastic force generated by the torsion spring 65, the guide rail 61 rotates upward 90 degrees, entering a vertically open state.
[0080] When the guide surface of the guide rail 61 is in a closed state near the upper surface 11 of the base plate 10, the height of the guide rail 61 protruding from the upper surface 11 of the base plate 10 is preferably set lower than the height of the rolling element 51 protruding from the upper surface 11. In this way, for some specific application scenarios, it is possible to choose not to open the guide rail 61, but the guide rail assembly 60 will not affect the normal use of the rolling transmission assembly 50.
[0081] like Figure 2 As shown, a support base 70 is provided on the lower surface 12 of the base plate 10. The support base 70 can be located at the midpoint between the front edge 13 and the rear edge 14 of the base plate 10. Multiple support bases 70 can be arranged at equal intervals along the length of the base plate 10. When the anti-collision guidance device 100 is in use, these support bases 70 serve to support the overall weight.
[0082] It should be understood that multiple anti-collision guide devices can be installed at the threshold, and these anti-collision guide devices 100 together protect the threshold along its entire length.
[0083] In other alternative embodiments, the base plate 10 may also be connected to the cargo compartment floor by means of other forms of connection devices, such as sliding pull-out connection devices, etc.
[0084] By employing the anti-collision guiding device according to the present invention, the transition portion at the front edge of the base plate can reliably guide the container onto the top of the rolling element, preventing the container from impacting the rolling element from the side and reducing the possibility of damage to the rolling element.
[0085] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.
Claims
1. A collision avoidance guidance device for an aircraft cargo door, comprising: A base plate having an upper surface and a lower surface, as well as a front edge and a rear edge; as well as A rolling conveyor assembly, which is mounted on the upper surface of the base plate; Its features are, The base plate of the anti-collision guide device has a transition section located at the front edge of the anti-collision guide device. The transition section has a sloping surface with a front edge relatively far from the rolling transmission assembly and a rear edge relatively close to the rolling transmission assembly. When the base plate of the anti-collision guide device is placed horizontally, the height of the leading edge is lower than the height of the trailing edge, and the height of the trailing edge of the ramp surface is higher than the upper surface of the base plate but not higher than the top of the rolling transmission assembly. The collision avoidance guide device further includes a hinge assembly located at the rear edge of the base plate, the hinge assembly being configured to pivotally connect to the base plate. The hinge assembly includes: A hinge connector is attached to the base plate. A hinge support base, which can be fixed to a mounting plate in the aircraft cargo hold; and A hinge pivot, wherein the hinge support is rotatably connected to the hinge connection seat via the hinge pivot.
2. The anti-collision guidance device as described in claim 1, characterized in that, The rolling transfer assembly includes a rolling element and a bracket that rotatably holds the rolling element on the upper surface of the base plate. When the base plate of the anti-collision guide device is placed horizontally, the height position of the rear edge of the ramp surface is lower than the height position of the top of the rolling element.
3. The anti-collision guidance device as described in claim 1, characterized in that, The anti-collision guiding device further includes a guide rail assembly with a guide surface, the guide rail assembly being disposed at opposite first and / or second side edges of the base plate. Furthermore, the guide rail assembly includes an open state and a closed state. When the guide rail assembly is in the open state, the guide surface is vertical to the upper surface of the base plate; When the guide rail assembly is in the closed state, the guide surface moves away from the vertical position and closer to the upper surface of the base plate.
4. The anti-collision guidance device as described in claim 3, characterized in that, The guide rail assembly includes: A guide rail base, wherein the guide rail base is fixed to the base plate; Guide rail, the guide rail having the guide surface; and A pivot shaft, wherein the guide rail is rotatably mounted on the guide rail base via the pivot shaft; The guide rail is positioned such that when open, its height on the upper surface of the base plate is higher than the height of the rolling transmission assembly, and when closed, its height on the upper surface of the base plate is lower than the height of the rolling transmission assembly.
5. The anti-collision guidance device as described in claim 4, characterized in that, The guide rail assembly also includes a locking device for locking the guide rail in a closed state.
6. The anti-collision guidance device as described in claim 1, characterized in that, The hinge assembly further includes a hinge locking part, which is configured to lock the hinge connector and the hinge support at a set angle.
7. The anti-collision guidance device as described in claim 1, characterized in that, The height of the leading edge of the ramp surface is not lower than the height of the upper surface of the base plate, and The slope surface of the transition section is inclined at an angle of 15-35 degrees relative to the horizontal plane.
8. The anti-collision guidance device as described in claim 1, characterized in that, The transition section also includes a leading edge wall and an attachment wall, as well as a recess located on the opposite side of the slope surface. The attachment wall is used to attach to the base plate, and a support pad is embedded in the recess.
9. The anti-collision guidance device as described in claim 1, characterized in that, The anti-collision guidance device also includes a plurality of support pads disposed on the lower surface of the base plate.