1. Connection system for producing an aligned connection between first and second tool parts, comprising a spigot projecting from the first tool part, and a spigot-receiving recess formed in the second tool part, the spigot and the recess having correspondingly shaped, non-circular respective cross-sections, the spigot and the recess being sized to enable the spigot to be inserted into the recess without expanding the recess or compressing the spigot.
2. The connection system according to claim 1, wherein the cross-sectional size of the spigot is smaller than the cross-sectional size of the recess, so that the spigot is spaced inwardly from a surface defining the recess.
3. The connection system according to claim 1 wherein the cross-sectional shape of the spigot and the recess is elliptical.
4. The connection system according to claim 1 wherein an outer end of the spigot is beveled.
5. The connection system according to claim 4 where an apex angle formed by the bevel is in the range of 1 to 10 degrees.
6. The connection system according to claim 5 wherein the apex angle is in the range of 1 to 5 degrees.
7. The connection system according to claim 5 wherein the apex angle is substantially 3 degrees.
8. The connection system according to claim 1 wherein the spigot has a length l and a longest cross-section d, the ratio ld being less than 1.0.
9. The connection system according to claim 1 wherein the ratio ld is less than 0.5.
10. The connection system according to claim 1, further including a fastener for securing the tool parts together.
11. The connection system according to claim 1, wherein the fastener comprises a screw passing through a through-hole formed in one of the tool parts and threadedly attached in the other tool part.
12. The connection system according to claim 11 wherein the fastener extends along a common center axis of the spigot and the recess.
13. The connection system according to claim 1 wherein each of the spigot and the recess includes a channel extending therethrough, the channels being in communication with each other for conducting a fluid from one tool part to the other.
14. The connection system according to claim 1 wherein the first tool part includes a first flat bearing surface portion disposed adjacent the spigot, the second tool part including a second flat bearing surface portion disposed adjacent the recess and contacting the first bearing surface portion.
15. The connection system according to claim 1, wherein one of the tool parts comprises a boring head, and the other tool part comprises a cutting bit holder.
16. The connection system according to claim 1 wherein one of the tool parts comprises a boring head, and the other tool part comprises a machine tool.
17. The connection system according to claim 1 wherein one of the tool parts comprises a spacing disk for joining the first tool part to another tool part.
18. A connection system for providing an aligned connection between first and second tool parts, wherein the first tool part comprises a spacing disk connected to an additional tool part, the connecting system comprising a spigot projecting from the first tool part, and a spigot-receiving recess formed in the second tool part, the spigot and the recess having correspondingly shaped, non-circular respective cross-sections, the spigot and the recess being sized to enable the spigot to be inserted into the recess without expanding the recess or compressing the spigot.
19. The connection system is according to claim 17 wherein the additional tool part includes an additional spigot projecting therefrom; the first tool part including an additional spigot-receiving recess formed therein; the additional spigot and the additional recess having correspondingly shaped, non-circular respective cross-sections, the additional spigot and the additional recess being sized to enable the additional spigot to be inserted into the additional recess without expanding the additional recess or compressing the additional spigot.
20. A tool part having a connection portion comprising a spigot of non-circular cross-section and adapted to be received in a correspondingly shaped recess of another tool part, wherein an outer end of the spigot is beveled, the bevel forming an apex angle in the range of 1 to 10 degrees, an inner portion of the spigot being of constant cross-section as seen in a section plane containing a center axis of the spigot.
21. A tool part having a connection portion comprising a spigot of non-circular cross section and adapted to be received in a correspondingly shaped recess of another tool part, wherein the spigot has a length l and a largest cross-section d, the ratio ld being less than 1.0.
22. The connection system according to claim 20 wherein the ratio ld is less than 0.5.
23. A tool part having a connection portion comprising a recess formed therein, the recess being of non-circular cross-section and adapted to receive a correspondingly shaped spigot of another tool part, wherein the recess has a length l and a longest cross-section d, the ratio ld being less than 1.0.
24. The tool part according to claim 22 wherein the ratio is less than 0.5.
25. A spacing disk for spacing-apart a pair of tool parts, the spacing disk including first and second sides, a spigot projecting from the first side and adapted to be received in a correspondingly shaped recess of one of the tool parts, the spigot being of non-circular cross-section; a recess formed in the second side and adapted to receive a correspondingly shaped spigot of the other tool part, the recess being of non-circular cross-section.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus for laying underground electric cables, comprising:
a vehicle (2) longitudinally movable over a trench (3) arranged to receive at least one electric cable (21);
a first deposition unit (12) to form a base layer (13) of inert material at the bottom of said trench (3);
at least one guide structure (20), having an inlet end portion (20a) turned towards the vehicle (2) front, to engage at least one stretch of said cable (21), and an outlet end portion (20b) disposed at a lower position and turned to the back of the first deposition unit (12) for laying the cable (21) on said base layer (13);
a second deposition unit (30) operating at the rear of the guide structure (20) to form a covering layer (31) of inert material upon the base layer (13) and the cable (21).
2. An apparatus as claimed in claim 1, further comprising at least a first compacting unit (17) operatively interposed between the first deposition unit (12) and the outlet end portion (20b) of said guide structure (20) for compacting the base layer (13) deposited at the trench (3) bottom.
3. An apparatus as claimed in claim 2, wherein said compacting unit (17) comprises a vibrating plate (18) acting against the base layer (13) by a lower surface thereof (18a) having a substantially V-shaped cross-section outline.
4. An apparatus as claimed in claim 3, wherein said V-shaped outline has a rounded vertex in the form of an arc of a circle of a radius substantially corresponding to half diameter of the cable (21).
5. An apparatus as claimed in claim 1, wherein said first deposition unit (12) comprises at least a first conveying duct (14) connected at the upper part thereof with feed means (15) for said inert material and at the lower part thereof with a downwardly-turned discharge opening (16).
6. An apparatus as claimed in claim 5, wherein said first conveying duct (14) and said first discharge opening (16) have a width reduced by an amount of at least 10% relative to the width of said trench (3).
7. An apparatus as claimed in claims 4 and 5, wherein said first discharge opening (16) is delimited at the rear part thereof by an outlet edge (16a)) disposed at a higher level than the lower surface (18a) of said vibrating plate (18).
8. An apparatus as claimed in claim 7, wherein said vibrating plate (18) has a lead-in portion (18b) rising from said lower surface (18a) in the direction of the outlet edge (16a)) of the discharge opening (16), and terminating at a higher level than said outlet edge (16a)).
9. An apparatus as claimed in claim 5, wherein at least one presser roller (28) is associated with the outlet end portion (20b) of the guide structure (20) and it acts elastically against the cable (21) to push it towards the base layer (13) laid at the trench (3) bottom.
10. An apparatus as claimed in claim 5, wherein said guide structure (20) has at least one central portion (20c) laterally disposed relative to said first conveying duct (14).
11. An apparatus as claimed in claim 1, wherein said second deposition unit (30) comprises a second conveying duct (32) connected at the upper part thereof with feed means (33) for said inert material, and at the lower part thereof with a second downwardly-turned discharge opening (34).
12. An apparatus as claimed in claim 11, wherein said second conveying duct (32) and said second discharge opening (34) have a width reduced by an amount of at least 10% relative to the width of said trench (3).
13. An apparatus as claimed in claim 11, wherein said second deposition unit (30) has adjustment means (35) operating at an outlet edge (34a) located at the rear of the second discharge opening (34) to adjust thickness of said covering layer (31).
14. An apparatus for laying underground electric cables, in particular as claimed in claim 1, wherein said vehicle (2) comprises a first van (4) and a second van (5) removably engaged in mutual alignment and respectively carrying the first deposition unit (12) and second deposition unit (30).
15. An apparatus as claimed in claim 1, wherein said vehicle (2) comprises adjustable suspension means (38) operatively associated with respective wheels (8, 9, 10) of the vehicle for modifying the height of said first and second deposition units (12, 30) and of said guide structure (20) relative to the trench (3) bottom.
16. An apparatus as claimed in claim 14, wherein said first and second vans (4, 5) are mutually in engagement by means of at least one fluid-operated connecting actuator (6).