US3145973A

US3145973A - Line stringing block

Info

Publication number: US3145973A
Application number: US219457A
Authority: US
Inventors: Macfarlane John
Original assignee: THEODORE D BROSS LINE CONSTRUC
Current assignee: THEODORE D BROSS LINE CONSTRUC; THEODORE D BROSS LINE CONSTRUCTION CORP
Priority date: 1962-08-27
Filing date: 1962-08-27
Publication date: 1964-08-25
Anticipated expiration: 1981-08-25

Description

l1g 25, 1964 J. MACFARLANE LINE STRINGING BLocx 2 Sheets-Sheet 1 Filed Aug. 27. 1962 INVENToR. z/a//A/ Mfr/mn f Ariat/la7 Aug. 25, 1964 J. MACFARLANE LINE: STRINGING` BLOCK 2 Sheets-Sheet 2 Filed Aug. 27. 1962 1N V EN TOR.-

United States Patent() 3,145,973 LINE STRINGING BLOCK .lohn Macfarlane, Hartford, Conn., assignor to The Theodore D. Bross Line Construction Corporation, Hartford, Conn., a corporation of Connecticut Filed Aug. 27, 1962, Ser. No. 219,457 11 Claims. (Cl. 254-134.3)

This invention relates to line Stringing blocks of the type used in Stringing multiple high voltage transmission lines and the like and more particularly to improvements in automatic tripping guide roller means therefor.

Line Stringing blocks of the type embodying the present invention are commonly used for Stringing transmission lines over extended distances and over all types of terrain. They are particularly adapted for use in Stringing lines which comprise a pair of conductors and generally include a frame having a drum rotatably mounted therein. A centrally disposed annular guide groove is usually formed in the drum to receive and guide the pulling cable or rope, and spaced sheaves are provided, one on either side of the drum, to receive the transmission lines as they are drawn through the Stringing block.

In the line Stringing operation, Stringing blocks are suspended vertically from the cross-arms of line towers and one end of a pulling rope or cable is threaded Successively through each block. A substantially triangularly shaped, articulated running board attached at its apex to the opposite end of the pulling cable leads the transmission lines through the Stringing blocks as the pulling the cable is drawn therethrough, the transmis- Sion lines being attached to the base of the running board in spaced apart relation equal to the spacing of the sheaves in the Stringing block.

It can be readily understood that, particularly in rough terrain, the line towers are seldom diposed in a straight line and that the vertical disposition of the cross-arms with respect to each other varies from one tower to the next. Such conditions naturally pose complex Stringing problems further complicated by the great weight of the pulling cable and transmission lines and the severe lateral forces acting upon the Stringing blocks generated as the cable is drawn therethrough. Such forces cause the Stringing blocks to sway and swing on the line tower arm and even to be pulled into positions near horizontal to the ground.

T o prevent the pulling cable from slipping out of the guide groove formed therefor in the drum and becoming jammed or fouled in the Stringing block under such conditions, the blocks are usually provided with a pair of spaced guide rollers on opposite sides of the drum to guide the pulling cable and to retain it Within the guide groove. Such rollers must, however, be adapted to spring apart upon engagement by the running board to permit its passage through the block. It is especially important that both rollers spring apart substantially Simultaneously. If only one roller should spring away, the running board would be deilected from its proper path through the block and the transmission lines would 'most probably become jammed or fouled in the block, thus causing delays and unnecessary expense before the Stringing operation could be continued.

It is therefore the primary object of the present in- Vention to provide improved pulling cable guide means for line Stringing blocks which will guide the running board into the Stringing `block in proper alignment for passage therethrough and will automatically spring out of the path of the running board as it enters the Stringing block.

It is a further object of the present invention to pro- 3,145,973 Patented Aug. 259, 1964 vide improvements in pulling cable guide roller structure for line Stringing blocks which will insure automatic re'- lease of the guide rollers and simultaneous movement thereof out of the path of the running board as it enters and leaves the line Stringing block.

Another object of the present invention is to provide improvements in guide roller means for line Stringing blocks which are particularly adapted to multiple line Stringing and which are suitable for use with conventional transmission lines of various diameters.

Another object of the present invention is to provide automatic tripping guide means for line Stringing blocks which is Simple in construction, efficient in use and yet inexpensive to manufacture.

Still another object of the present invention is to provide automatic tripping guide means for line Stringing blocks which will operate with equal eiciency and effectiveness in inclement weather as well as in fair weather.

A still further object of the present invention is to provide automatic tripping means for line Stringing block guide rollers which will function in the intended manner regardless of the lateral stresses applied thereto during the line Stringing operation.

Another object of the present invention is to provide automatic tripping guide roller means for line Stringing blocks which will function to permit substantially simultaneous springing apart of both guide rollers upon engagement of either one or both of the guide rollers by the running board.

It is still another object of the present invention to provide improvements in guide roller means for line Stringing blocks which will permit automatic tripping of the guide rollers upon engagement therewith by the running board to allow passage of the running board and transmission lines attached thereto through the Stringing block without jamming or fouling the lines.

Additional objects and advantages of the present invention will appear from the following description in which a preferred embodiment has been set forth in detail in conjunction with the accompanying drawings in which:

FIG. 1 is a top plan view of a line Stringing block incorporating the present invention and shown with the running board in broken lines in relative position for entry and passage therethrough.

FIG. 2 is an end elevational View of the line Stringing block of FIG. l Showing the guide rollers in closed position for guiding the pulling cable and, in broken lines, in open position to permit the running board to pass therebetween.

FIG. 3 is a side elevational view of Said line Stringing block further illustrating the guide roller means of the present invention.

FIG. 4 is an enlarged, fragmentary, side elevational View, in partial section, of the guide roller structure and automatic tripping means therefor taken on line 4-4 of FIG. 5.

FIG. 5 is an enlarged, fragmentary, end elevational View, in partial section, of the guide rollers and automatic tripping means therefor shown in closed position for guiding the pulling cable.

FIG. 6 is a fragmentary Side elevational view, in partial section, further illustrating the action of the automatic tripping means of the present invention.

FIG. 7 is an enlarged, fragmentary, end view, in partial section, showing the guide rollers in open position to permit the running board to pass therebetween.

FIG. 8 is an enlarged, fragmentary, plan View, in partial section, illustrating the guide roller mounting means used in the present invention.

FIGS. 9 and l0 further illustrate the releasing action of the novel latching means employed in the present invenn b tion to insure simultaneous release of the guide roller means.

As Shown in the drawings, my invention is embodied in a Stringing block of conventional design which includes a frame 6 comprising spaced, upright, parallel side members 7-7 and upper and

lower cross-members

8 and 9, respectively. The upper and

lower cross-members

8 and 9 extend transversely to the side members 7--7 and are secured at their ends to the said side members, as shown in FIG. 2 of the drawing, to form a substantially rectangular configuration therewith. A centrally located fitting 10, of any suitable type, is provided on the upper cross member 8 to permit attachment of the block to the crossarm of the line tower by a chain or any other suitable means commonly employed for the purpose. The cross member 8 is detachably secured to the upper ends of side members 7 7 to permit removal of the Stringing block from the transmission lines after completion of the stringing operation.

The frame 6 also includes a rectangular, horizontally disposed supporting member 11 which is secured to the side members 7-7 intermediate the ends thereof, as best shown in FIGS. 2 and 3 of the drawings. Opposed pairs of spaced arms 12-12 are secured at their interior ends centrally of the cross members 8 and extend perpendicularly outwardly from opposite sides thereof in a direction Substantially perpendicular thereto and parallel with the supporting member 11, as shown in FIGS. l and 2.

The side members 7--7 support the ends of a shaft 13 on which a drum 14 is rotatably mounted. The drum 14 is preferably formed with a centrally located annular guide groove 15 therein. A sheave 16 is also rotatably mounted on the shaft 13 on each side of the drum 14 to receive the transmission lines drawn through the Stringing block during the Stringing operation.

Pairs of elongated, spaced guide rollers 17-17 are mounted on the frame 6 at opposite sides of the drum 14 in a substantially upright position transverse to the axis of rotation of the drum 14. Each pair of rollers is aligned with the annular guide groove 15 in the drum to permit a pulling cable 17-a to pass through the block 5 between the spaced rollers and be retained in said groove, as Shown in FIGS. 1, 2 and 3.

The guide roller means provided by the present invention is substantially the same at each side of the drum 14 and preferably includes the pair of rollers 17-17 mounted by ball bearings 18-18 or the like to rotate on shafts 19-19. The shafts 19-19 are aliixed at their lower ends to brackets 20-20, which are arranged in opposed, overlapping relation and are provided with aligned holes Ztl-a therethrough. Said holes receive a bolt 21 which is secured to a mounting plate 22 on the supporting member 11 and supports the guide rollers for pivotal movement in opposite directions about an axis extending Substantially normal to the axis of rotation of the drum 14.

In order to insure consistent, dependable operation, it is desirable to mount the rollers 17-17 with their axes lying in a common plane parallel with the axis of the drum 14. This may be done in any suitable manner, but in the embodiment of the invention shown herein the lower end of the shafts 19--19 are notched to form Semicylindrical end portions 19-a-19-a thereon which are welded or otherwise secured to the juxtaposed faces of the brackets 29-20. As can be clearly seen from FIG. 5 the rollers are biased in opposite directions about their common pivotal axis by tension springs 23--23 secured in any desired manner between the mounting plate 22 and the outer ends of the brackets 20-20. The said end portions 19-a-19-a of the shafts 19-19 are bevelled, as at 19-b, to provide abutment Surfaces thereon for a purpose to be defined later.

Each pair of guide rollers 17--17 is restrained against swinging movement and in spaced, upright parallel relationship against the biasing force of the springs 23-23 by a latch member 24 mounted between the outer ends of the arms 12-12 for pivotal movement about a pin 25 having its axis parallel with the axis of the bolt 21. The latch member 24 is of a substantially inverted U-Shaped conguration, as Shown in FIG. 9, comprising a pair of outwardly diverging arms 26-26 formed with parallel terminal portions 26-a-26-a adapted to be received in slots 27-27 provided in the upper end portions of the Shafts 19-19 to retain the said shafts and rollers in parallel relationship against the bias of the springs 2323 and in alignment with the groove 15 in the drum 14. A web 28 is provided on the edge of the latch member 24 to reinforce the arms 26-26 and to resist deformation thereof under the severe forces encountered in Stringing transmission lines. It will be noted that the web is provided only on the edge of the latch which faces the running board, and that the opposite edge iS left unobstructed to permit sliding disengagement of the shafts 19-19 from the arms of the latch member as the running board engages the rollers 17-17.

The mounting plate 22 on which the brackets 20--20 are rotatably mounted is yieldingly held in position against the vertical side of the supporting member 11 by spring-pressed bolts 29-29 to permit limited tilting movement, with respect to the drums 14, of both the plates 22 and the guide rollers 17-17 in the direction of movement of the pulling cable 17-a upon engagement of the running board 30 with the guide rollers 17-17. The mounting plate 22 is formed with spaced, inwardly extending projections or fingers 31-31 which overlie the upper surface of the supporting member 11, as best shown in FIGS. 4 and 6 of the drawings, to retain the plate in its proper position.

In using a Stringing block incorporating the automatic tripping guide roller means provided by the present invention, the pulling rope or cable 17-a, Shown in broken lines in FIG. l, is threaded through the pairs of parallel guide rollers 17-17 and over the drum 14 from left to right as viewed in FIGS. l, 3 and 4. As the pairs of guide rollers are each aligned with the annular groove 15 in the drum, the pulling cable is therefore guided into and retained in the said groove while the transmission lines 32-32 are drawn by the pulling cable toward the stringing block. To facilitate Stringing the transmission lines, it is customary to interpose the running board 30 between the pulling cable and the transmission lines. The running board is generally of articulated construction and triangularly shaped, being secured to the pulling cable at its apex and having a pair of transmission lines attached in spaced apart relation to its base. As the running board approaches and strikes the first or left pair of rollers upon entering the Stringing block, the rollers are urged inwardly toward the drum 13 under the impact of the running board from their normal guiding position as seen in FIG. 4 to that shown in FIG. 6. The Spring retained bolts 29-29 yield against the bias of their springs permitting the rollers and their mounting plate to tilt inwardly on the supporting member 11 toward the drum 14. As the left pair 0f rollers 17h17 tilts inwardly, the upper ends of the shafts 19-19 are disengaged from the latch 24 and the rollers are immediately caused to Swing apart under the influence of the springs 23--23 and out of the path of the entering running board aS shown in FIG. 7 and in broken lines in FIG. 2.

As the running board is drawn over the drum and through the Stringing block, it engages the second or right pair of rollers on the opposite Side of the Supporting member 11 aS can be seen from FIGS. 1, 3 and 6. Likewise, the engaging force of the running board against the rollers upon leaving the Stringing block overcomes the spring retained bolts 29-29 forcing the rollers and their mounting plate to tilt outwardly away from the drum about the lower edge of the Supporting member 11 as at 33. As the rollers are forced outwardly, the shafts 19-19 become disengaged from the latch member 24 as previously described and under the inuence of the springs 23-23 rotate in opposite directions about their common pivot to swing the rollers apart and out of the path of the exiting running board.

As the running board passes through the Stringing block, it deposits the spaced apart transmission lines attached to its base in the grooves of the sheaves 16--16 which are correspondingly spaced within the Stringing block. The lines 32-32 remain supported by the block until they are later permanently attached to the insulators on the transmission towers.

As can be seen from FIGS. 5 and 7 of the drawings the bevelled portions 19-b-19-b provided on the terminal portions 19-a-19-a of the guide roller shafts form abutment surfaces to limit the swinging movement of the shafts about the bolt 21. As can be seen from FIGS. 7 and 8, as the rollers swing apart, the said abutment surfaces engage the underside of the brackets 20--20 limiting the movement of relative movement of the rollers about the bolt 21. The biasing force of the springs 23-23 retain the said abutment surfaces in engagement with the underside of the brackets 20-20 until the guide rollers are rotated into upright, parallel guiding position and latched against the bias of the springs 23a-23.

The foregoing description is considered as illustrative only of the principles of my invention. The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specilication, as various changes in the details of construction may be resorted to Without departing from the spirit thereof.

Conditions frequently encountered in strinigng transmission lines often cause the running board to be drawn into engagement with the guide rollers of the Stringing block at an angle. Under such conditions, when using Stringing blocks having only conventional guide roller latch tripping means, it is not unusual for only one of the guide rollers to become unlatched and to swing out of the path of the running board while the other remains in latched position causing the pulling cable, transmission lines and/ or running board to become jammed or fouled in the Stringing block.

A further novel feature of the automatic tripping guide roller structure of the present invention, shown in FIGS. 9 and l0 of the drawings, insures simultaneous release of both guide rollers from their guiding position to prevent such jamming or fouling. If the running board, when entering the block, should strike the guide rollers at an angle causing only one of the rollers to tilt toward the drum and become slidingly disengaged from the latch member to swing out of the path of the running board, the biasing force of the spring 23 continues to urge the remaining roller to swing outwardly about its axis of rotation. The pivotally mounted latch member 24 is therefore caused to rotate or pivot about the pin 25 toward the roller. The simultaneous rotation of the latch member about the pin 25 and the guide roller about its parallel axis of rotation on the bolt 21 causes the terminal portion 26-a of the arm 26 to be rotated out of engagement from the slot Z7 thereby permitting the guide roller to swing fully out of the way of the entering running board. It is obvious that when forming the slots 27-27 in the upper ends of the roller shafts 19-19 care must be taken to ascertain that the width of the slot is sufficient to permit the above-described rotational disengagement of the latch member arm therefrom. While the aforesaid action of the latch member and guide roller was necessarily sequentially described, in actual operation upon disengagement of one guide roller from the latch member the disengagement of the other would take place so rapidly that for all practical purposes both rollers would swing apart out of the Way of the running board substantially simultaneously.

From the foregoing, it will be apparent that the present invention provides simple, yet highly eflicient improvements in automatic tripping guide roller means for conventional line Stringing blocks. The novel structure permits the pulling cable or rope to be retained in its proper position as its is drawn through the Stringing block and func- 6 tions to automatically release and simultaneously swing the guide roller means out of the path of an approaching running board to permit transmission lines to be drawn through the block without jamming or fouling.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in the specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention.

I claim:

l. A line Stringing block of the type used in a transmission line Stringing operation, wherein transmission lines are attached to a running board which is drawn through the Stringing block by a pulling cable, the said Stringing block comprising a frame, a drum mounted in said frame for rotation about a horizontal axis and having an annular groove therein to receive said line pulling cable, a Supporting member on said frame, guide members mounted on said supporting member aligned with said groove and normally disposed in guiding position thereon in spaced relation to receive said pulling cable therebetween and guide it over said drum to retain it in said groove as it passes through said block, latch means engageable with and normally retaining said guide members in said guiding position, and means on said frame effecting simultaneous movement of said guide members from said guiding position upon engagement by said running board whereby the running board may pass through said block unobstructed by said guide members.

2. In a Stringing block for use in a transmission line Stringing operation wherein transmission lines are attached to a running board which is drawn through the Stringing block by a pulling cable, said Stringing block including a frame, a drum mounted in said frame for rotation about a horizontal axis and having an annular groove therein to receive said line pulling cable, the improvement comprising: a supporting member on said frame, a mounting plate yieldingly secured to said supporting member spaced from and adapted for limited movement with respect to the drum in a direction substantially transverse to said horizontal axis, guide members on said mounting plate aligned with said groove and normally disposed in guiding position thereon in spaced relation to receive said pulling cable therebetween and guide it over said drum to retain it in said groove aS it passes through said block, latch means engageable with and normally retaining said guide members in said guiding position, and spring means on said frame cooperative with said guide members for effecting simultaneous movement of said members from said guiding position upon engagement by said running board to permit the running board to pass through said block unobstructed by said guide members.

1i. In a Stringing block for use in a transmission line Strlnging operation, wherein transmission lines are attached to a running board which is drawn through the strmgmg block by a pulling cable, said Stringing block including a frame, a drum mounted in said frame for rotation about a horizontal axis and having an annular groove therein to reecive said line pulling cable, the improvement comprising: a supporting member on said frame, a mounting plate yielding secured on said supporting member for limited pivotal movement thereon in a direction substantially the same as the direction of travel of said pulling cable, adjacent brackets on said plate mounted for limited pivotal movement in opposite directions about a common axis, guide members mounted on each of said brackets in spaced relation with said groove, said guide members being normally disposed to receive said pulling cable therebetween and guide it over said drum retaining it in said groove as it passes through said block, latch means engageable with and normally retaining said guide members in guiding position aligned with said groove, spring means cooperative with and normally urging said brackets and guide members carried thereon to swing in opposite directions about said common axis to effect movement of said guide members from said guiding position upon engagement by said running board to permit passage of said running board through said block unobstructed by said guide members.

4. The structure dened in claim 3 wherein said frame is substantially rectangular and vertically disposed, and said supporting member comprises side members secured intermediate their terminal portions to said frame and end members connecting said terminal portions to form a substantially rectangular member lying in a plane transverse to the plane of said frame.

5. The structure set forth in claim 3 including means on said guide members engageable with said brackets to limit the pivotal movement of said brackets and guide members in opposite directions about said common pivotal axis.

6. In a line Stringing block for use in a transmission line Stringing operation wherein transmission lines are attached to a running board which is drawn through the Stringing block by a pulling cable, said Stringing block including a frame, a drum mounted in said frame for rotation about a horizontal axis and having an annular groove therein to receive said line pulling cable, the improvement comprising: a supporting member on said frame, guide members mounted on said supporting member aligned with said groove and normally disposed in guiding position thereon spaced to receive said pulling cable therebetween and guide it over said drum retaining it in said groove as it passes through said block, an arm supported by the frame extending outwardly therefrom and aligned with said groove, latch means carried by said arm engageable with and normally retaining said guide members in said guiding position, and means on said frame effecting disengagement of said guide members from said latch means for simultaneous movement of said guide members from said guiding position upon engagement by said running board to permit passage of said running board through said block unobstructed by said guide members.

7. The structure set forth in claim 6 wherein said latch means includes a pair of outwardly diverging arms of substantially inverted U-shaped configuration and having inturned parallel terminal portions on said arms engageable with said guide members.

8. A line Stringing block of the type used in a transmission line Stringing operation wherein transmission lines are attached to a running board which is drawn through the Stringing block by a pulling cable, the said block comprising a frame, a drum mounted in said frame for rotation about a horizontal axis and having an annular groove therein to receive said line pulling cable, a supporting member on said frame, guide members mounted on said supporting member aligned with said groove and normally disposed in guiding position thereon spaced to receive said pulling cable therebetween and guide it over said drum retaining it in said groove as it passes through said block, each of said guide members being provided with upper and lower end portions, said upper end portion of each being formed with a slot extending therethrough transverse to the said horizontal axis, an arm on said frame extending outwardly therefrom aligned with said groove, a latch member pivotally mounted on said arm for limited pivotal movement about an axis transverse to said axis of rotation, said latch member being of a substantially inverted U-shaped configuration and including a pair of outwardly diverging arms, inturned, parallel terminal portions on said arms adapted to engage said slots to retain said guide members in said guiding position and means on said frame eifecting disengagement of said parallel terminal portions from said slots for simultaneous movement of said guide members from said guiding position upon engagement therewith by said running board permitting passage of said running board through said block unobstructed by said guide members.

9. The Stringing block set forth in claim 8 wherein the said means permitting disengagement of said parallel terminal portions includes a mounting plate carried by said supporting member, said plate being yielding secured thereto for pivotal movement thereon opposite said drum in a direction transverse to said horizontal axis, said guide members being secured to and carried by said plate whereby when engaged by said running board, said members and plate pivot in the direction of travel of said running board, thereby causing disengagement of said terminal portions of the latch member from said slots permitting movement of said guide members from said slots.

10. The Stringing block dened in claim 1 including latch means engageable with and normally retaining said guide members in said guiding position, said guide members being disengageable from said latch means for simultaneous movement from said guiding position upon engagement by said running board to permit the running board to pass through said block unobstructed by the guide members.

1l. The stringing block as set forth in claim 8 wherein the guide members are mounted for limited pivotal movement in opposite directions about an axis transverse to the said horizontal axis of rotation and including spring means associated with and normally biasing said guide members to move in opposite directions upon disengagement of said terminal portions of said guide members from said latch.

References Cited in the le of this patent UNITED STATES PATENTS

Claims

1. A LINE STRINGING BLOCK OF THE TYPE USED IN A TRANSMISSION LINE STRINGING OPERATION, WHEREIN TRANSMISSION LINES ARE ATTACHED TO A RUNNING BOARD WHICH IS DRAWN THROUGH THE STRINGING BLOCK BY A PULLING CABLE, THE SAID STRINGING BLOCK COMPRISING A FRAME, A DRUM MOUNTED IN SAID FRAME FOR ROTATION ABOUT A HORIZONTAL AXIS AND HAVING AN ANNULAR GROOVE THEREIN TO RECEIVE SAID LINE PULLING CABLE, A SUPPORTING MEMBER ON SAID FRAME, GUIDE MEMBERS MOUNTED ON SAID SUPPORTING MEMBER ALIGNED WITH SAID GROOVE AND NORMALLY DISPOSED IN GUIDING POSITION THEREON IN SPACED RELATION TO RECEIVE SAID PULLING CABLE THEREBETWEEN AND GUIDE IT OVER SAID DRUM TO RETAIN IT IN SAID GROOVE AS IT PASSES THROUGH SAID BLOCK, LATCH MEANS ENGAGEABLE WITH