US2590338A - Pole climber with automatic impact drive - Google Patents

Description

i Fi I March 25, 1952 R, A, MERRlLL 2,590,338

POLE CLIMBER WITH AUTOMATIC IMPACT DRIVE Filed Jan. 20, 1951 VJ jig. '-/vv/ 52 INVENToR. u YJ/w 5% Patented Mar. 25, 1952 UNITED STATES PATENT GFFICE POLE CLIMBER WITH AUTOMATIC IMPACT DRIVE Roland A. Merrill, Van Nuys, Calif.

. Application January 20, 1951, Serial No. 206,965

14 Claims.

This invention relates to linesmans pole climbers or climbing irons. The general object of the invention is to provide a climber having means for automatically setting the claw Vof the climber into a pole to an adequate depth for safely sustaining the weight of the linesman, without requiring any effort on the part of the linesman other than that of simply imposing his Weight upon the climber.

When a linesman is ascending a pole, the action of setting the claws of the climbers into the pole is usually vigorous enough to embed them to an adequate depth to prevent them from slipping or tearing loose when the full weight is imposed thereon. However, when a linesman is moving horizontally around the pole he will often fail to set a claw of a climber suiciently deeply into a pole to prevent slipping and sometimes a bad fall will result from a claw tearing loose from the pole because of insuicient embedment.

My inventionA contemplates an automatic mechanism for imparting a sharp blow to the pole, from a striker operating under spring pressure which is stored up when the weight of the linesman is applied to the climber. Means is provided for releasingthe striker when a predetermined spring loading has been reached, so that the full spring load may be utilized for driving the striker against the claw in striking a blow that will drive the claw deeply into the pole.

A further object of the invention is to provide in a climber having such an automatic striking mechanism, a means for automatically resetting the striker mechanism for a subsequent operation, when the weight of the linesman is released from the climber.

A specic object of the invention is to provide a climber having an automatic claw setting mechanism as outlined above, and which is of relativelysimple, durable and inexpensivey construction.

Other objects will become apparent in the ensuingdetailed description of the invention, taken together with the appended drawings, in which:

Fig. 1 is a side view of a climber embodying my invention;

Fig. 2 is an axial sectional view of the climber, with the parts showing the relative positions assumed at an early stage in the loading operation, and with the unstressed position of the parts indicated by dotted lines;

Fig. 3 is an axial sectional view of the climber showing the parts in the position in which the striker actuating spring is fully loaded and the striker is about to be released for its operating blow;

Fig. 4 is an axial sectional View of the climber showing the parts' in the relative positions just prior to the striking of the blow; j

Fig. 5 is a transverse sectional view taken on the line 5--5 of Fig. 2;

Fig. 6 is a transverse sectional View taken on the line 6 6 of Fig. 2; v

Fig. '7 is a transverse sectional View taken on the line 'I-'I of Fig. 2; and

Fig. 8 is a detail of one of the trigger pawls.

Referring now to the drawings in detail, I have shown, as an example of one form in which the invention may be embodied, a climber having a foot stirrup I0 adapted to extend beneath the instep of a linesmans shoe and to be secured thereto by a strap (not shown) extending through an eye I I in the outer extremity thereof, and strapped around the foot in a conventional manner whereby the climber is attached to the foot and the linesmans weight may be carried upon the stirrup I0.

The climber has a claw I2, provided with a sharp point for entering a telephone or electric power line pole, claw I2 being connected to the stirrup III through the medium of the automatic driving mechanism which will now be described.

Secured to an arm I3 forming an upward extension of the inner end of stirrup I0 is a casing I4 the upper portion of which denes a cylindrical chamber I5 in which an annular striker I6 is longitudinally slideable. Striker I6, as shown in the dotted line position of Fig. 3, normally rests against a shoulder I1 defining the lower extremity of chamber I5 and the upper extremity of a thickened lower wall portion of casing I4, in which is formed a pair of diametrically opposed longitudinal slots I8. A heavy coil spring I9, for actuating the striker, is interposed under compression between striker I6 and a collar 20 which is threaded into the upper end of chamber I5. The lower end of spring I9 is piloted in a counterbore in the upper end of striker I6. 'Collar 20 may have sockets 2| for engagement by a spanner wrench. The initial loading of spring I9 may be adjusted by adjusting collar 20 to different depths in casing I4. A bearing bushing 22 is threaded through collar 20.

Claw I2 is provided with an integral annular collar 47, to receive the impact of striker I6. A

cross-pin 23 extends therethrough and is secured therein. The ends'm of cross-pin 23 are keyed in slots I8to restrain claw I2 against rotation in casing I4 while allowing it to slide longitudinally therein. Claw I2 has a stem 24 which extends upwardly through a central bore in bushing 22 and is tted therein for free sliding movement. Claw I2 has a cylindrical main shaft portion 25 which is fitted into the bore of annular striker I6 for free sliding movement therein.

Stem 24 joins shaft portion 25 to define a squared annular shoulder 26. In the loading of spring I9 (Fig. 2) when the weight of the operator is imposed upon stirrup I0, shoulder 26 is engaged by a pair of pawls 21 each pivoted, on a pivot 28, in a recess 29 opening into the bore of striker I6. The recesses 29 are preferably spaced equidistantly around the circumference of striker I6. There may, for example, be three of the pawls 21 disposed at 120 intervals, (Fig. 6) in order that the loading may be well distributed. Each of the pawls 21 has at its lower end a shoulder 38 (Fig. 8) for engaging shoulder 2S of claw I2, and a nger 39 at the outer extremity of the shoulder 38, to engage the side of claw shaft 25 and thus limit the inward movement of the pawl. Each of the pawls is engaged by a split ring spring 33 disposed in an internal annular groove 3| in striker I6 and engaged in notchesv 32 in the pawls. The slots 29 are of sufcient depth so thatthe pawls 21 may retract outwardly to positions, as shown in Fig. 3, where they clear the shoulder 26 and allow the striker I6 to be driven by the loading spring I3 downwardly against collar 41, whereby to deliver a blow to the claw I2.

Projecting downwardly from the lower end of bushing 22 is a thin walled tubular pawl releasing plunger 33 which is adapted to enter the upper end of the bore of striker I6, to engage the pawls 21, and t move them outwardly until they are completely released from the shoulder 26. Bushing 22 has at its upper end a head 34 which is of non-circular shape so that a wrench may be applied thereto. The adjustment of bushing 22 is for the purpose of adjusting pawlrelease plunger 33 to the proper position for releasing pawls 21 at a point of maximum loading of spring I9. Plunger 33 has a counterbore 35 which, with stem 24, denes an annular space in which is received the upper portion of a light coil spring 36. The spring 35 is engaged under compression between bushing 22 at its upper end and, at its lower end, an annular groove 31 in shoulder 26. The function of spring 36 is to assure the return movement of claw I2 to a, starting position in which pin 23 is at the lower ends of slots I8, when the linesman raises his foot so as to elevate casing I4. This starting position must be attained in order that pawls 21 may reengage shoulder 2E.

Casing I4 has a reduced lower end portion 4U which has a cylindrical external wall forming a bearing surface for a locking sleeve 4I that is rotatably mounted thereon. Sleeve 4I has diametrically opposed L-shaped slots including vertical slot portions i12 adapted to register with casing slots I3, and including slightly inclined (helical) lateral slot portions 43. Slot portions 4.3 are adapted to receive the end portions of pin 23 when locking sleeve il is rotated, whereby to draw said end portions of the pin tightly against the lower ends of the slots I3 and to thereby lock the claw I2 in its starting position. Thus the Climber may be converted into a climber having conventional operational characteristics, the weight of the linesman being transmitted from casing I4 to sleeve 4I (through a shoulder 44 in casing I4 at the upper extremity of reduced end portion 40) and from sleeve 4I to pin 23.

A collar i5 is threaded into the lower end of casing I4, and has a radial flange 46 which functions as a retainer bearing against the lower end of locking sleeve 4I.

The operation of the climbers is as follows: One of the climbers is strapped to each foot with claws I2 directed inwardly toward each other so that they may be impaled in the post to be climbed. At the starting point pin 23 is at the bottom of slots I8 as indicated in dotted lines in Fig. 2, and pawls 21 have thus been permitted to move inwardly under the pull of ring spring 3i), and are engaged against shoulder 2G so that springs I9, 36 may be compressed. The point of the claw is pressed against the pole at a selected point, and the weight of the body is applied to the stirrup attached thereto. As the weight is applied, the claw will enter the post to a degree determined by the aggregate loading upon springs I9 and 43, and at the same time the springs will be compressed in accordance with the resistance of the wood to the penetration of the claw. An early stage in this loading operation is shown in Fig. 2, which shows the stirrup and casing I6 moving downwardly, compressing the springs. This movement continues until shoulder I? passes below pin 23. The loading movement is terminated by the engagement of shoulder 25 against the lower end of plunger 33 (Fig. 3) In the final stage of loading movement, the plunger 33 will engage and spread pawls 21. Thus the striker I6, which up to this point has been supported upon shoulder 26, will be released for downward movement relative to casing I4 and claw shaft 25. After the disengagement of the pawls, striker I1 will be propelled downwardly by the stored energy of compressed spring I3. During this interval, the weight of the operator upon stirrup il) will be transmitted through casing IG, plunger 33 and shoulder 26 to claw l2, which remains in a fixed position, impaled in the post. The striker I3 as it nears the end of its downward stroke, will strike a sharp blow against pin 23.

Upon contact with pin 23, striker I6 will release the kinetic energy stored therein during its downward travel, driving claw I2 more deeply into the post. Maximum possible travel of claw i2 under the blow, is determined by the distance that pin 23 projects above shoulder I1, the engagement of striker I6 against shoulder I1 terminating the downward travel of the striker in the chamber I5. Fig. 4 shows the extent of projection of pin 23 above shoulder I1 prior to the striking of the low, as determined by the engagement or shoulder 2S against plunger 33.

After the blow has been absorbed by the claw, the casing Ill will follow the claw downwardly until plunger 33 again makes contact with shoulder 26, thus establishing a solid supporting connection from the claw to the stirrup I. The load capacity of spring I9 is selected so as to obtain adequate setting of the claw into the post to prevent any possible disengagement when the full weight of the operator is loaded upon the stirrup I9. At the same time, the load capacity of the spring I9 must be suciently below the weight of the average operator so that it will be possible for the spring to be fully compressed to the fully loaded position of striker i3, before the full weight of the operator is applied to the stirrup. Otherwise, the striker could not be released.

rl`he preloading of the spring i9 may be varied within limits by adjusting the position of abutment collar 29. By reducing the preloading, the apparatus may be adjusted to a lighter person, and by increasing the preloading the apparatus may be adjusted to a heavier person.

By changing the position of plunger 33, the point of triggering of the pawls 33 to their disengaged positions, may be varied. Such adjustment likewise may be utilized for adjusting the climber to a lighter or heavier person. The earlier the point of disengagement, with reference to the loading of: spring I3, the less the compression of spring i9.

When the weight of the operator is released from the stirrup, and the casing I4 is moved upwardly, relative downward movement of claw I2 in relation to casing I4 will be assured by the operation of spring 36, i. e., claw I2 will be held by spring 36 against moving upwardly with casing I4 until the latter has returned to the position of Fig. l in which pawls 21 have reengaged above shoulder 26. This completes the cycle of operation of the apparatus.

I claim: 1. In a linesmans climber, a stirrup, an elongated casing secured to said stirrup, `a claw having a shaft extending into said casing, and having an abutment member, a striker slideable longitudinally within said casing and adapted to engage said abutment member, a spring under compression between the upper end of said striker and the upper end of said casing, for driving said striker downwardly relative to said shaft, a trigger element carried by said striker and releasably engageable with said shaft to load said spring by relative upward movement of said striker in said casing when the casing is moved downwardly under the weight of the operator, and means carried bythe upper end of said casing and rendered operative by the arrival of the casing at a downward limit of movement relative to said shaft, to release said trigger from its engagement with said shaft and thereby cause the striker to be propelled downwardly by the loaded spring and to strike a blow against said abutment member, whereby to drive said claw into a body engaged thereby. 2. In a linesmans climber, an elongated casing having means to secure the same to a linesmans shoe, a claw having a shaft extending into said casing and having an abutment member, an annular striker encircling said shaift and slideable longitudinally within said casing and relative to said shaft, for engagement with said abutment member, a spring under compression between the upper end of said striker and the upper end of said casing, for driving said striker downwardly, a plurality of trigger elements carried by said strikerin annular array and releasably engageable with said shaft to support said striker on the shaft while the casing is moved downwardly under the weight of the operator, whereby to load said spring, and means carried by the upper end of said casing and rendered operative by the arrival of the casing at a downward limit of movement relative to said shaft, to release said trigger from engagement with said shaft and thereby cause the striker to be propelled downwardly by the loaded spring, and to strike a blow against said abutment member, whereby to drive said 'claw into a body engaged thereby. v3. In a linesmans climber, an elongated casing adapted to be secured to a climbers shoe, a claw having a shaft extending into said casing and having an abutment member, a striker slidel '6 casing at a downward limit of movement relative to said shaft, to engage said trigger means and release said striker supporting connection, 'thereby to cause the striker to be propelled downwardly by theloaded spring and to strike a blow against said abutment member so as to drive said claw able longitudinally within said casing and along said shaft and adapted to engage said abutment member, a spring under compression between the upper end of said striker and the upper end of said casing. for driving said striker downwardly relative to said shaft, trigger means for establishing a releasable connection between said striker and said shaft to load said spring by supporting said striker on said shaft while the casing is moved downwardly under the weight of the operator, wherebyto load said spring and releasing means carriedby the upper end of said casing and rendered operative by the arrival off the into a body engaged thereby.

4. A climber as defined in claim 3, wherein said releasing means comprises a tubular member secured to Ithe upper end of the casing and projecting downwardly therein, said shaft having a` reduced stem extending upwardly through said tubular member and having a shoulder defined at the base of said stem, against which said tubular member is engageable to provide said solid support.

5. A climber as defined in claim 4, wherein said tubular member is spaced from said stem to dene an annular space, said climber including a relatively light coil spring the upper end of which is engaged in said annular space and the lower end of which is engaged against said shoulder, for effecting return movement of said shaft downwardly with reference to the casing when the casing is lifted.

6. In a linesmans climber, an elongated casing having means for securing the same to a linesmans shoe, a claw having a shaft extending into said casing and having an abutment member slideably engaged with said casing for preventing rotation of the claw with reference to the casing while allowing longitudinal movement of the shaft in the casing, an annular striker encircling said shaft and slideable longitudinally within said casing for engagement with said abutment member, a coil spring under compression between the upper end of said striker and the upper end of said casing, for driving said striker downwardly relative to said shaft, trigger means for establishing a releasable connection between said striker and said shaft to load said spring by supporting said striker on said shaft while the casing is moved downwardly under the weight of the operator, and means carried by the upper end of said casing and rendered operative by the arrival of the casing at a downward limit of movement relative to said shaft, to engage said trigger means and to release said striker supporting connection, and thereby cause the striker to be propelled downwardly by the loaded spring and to strike a blow against said .abutment member, whereby to drive said claw into a body engaged thereby.

'7. In a linesmans climber, an elongated casing having means for securing the same to a linesmans'shoe, a claw having a shaft extending into said casing and having an abutment pin extending transversely therethrough, said casing having a pair of opposed longitudinally extending slots in which the ends of said pin are engaged for preventing rotation of said claw relative to said casing while allowing longitudinal movement of the claw relative to the casing, an annular striker encircling said shaft and slideable longitudinally within said casing for engagement against said abntmentmember, a coil spring also encircling said' shaft within saidcasing and under' compres-- sion between the upper end of said striker and the upper end of said casing, for driving said striker downwardly relative to said shaft, trigger means for establishing a loading connection between said striker and said'shaft for supporting said striker on said `shaft while said casing is moved downwardly under a linesmans vs /eight,v whereby said coil spring willbeloaded, and means carried by the upper end of saidV casing and rendered operativev by the arrival of the casing at a downward limit of movement relative to said shaft, to engageA said trigger means so as to' release said loading connection and thereby cause the striker to be propelled downwardly by the loaded spring and to strike a blow against said abutment member, whereby to' drive said claw intoy a body engaged thereby.

8. A. climber as dened in claim 7, including a locking sleeve rotatably mounted on the lower end of said casing and having therein L-shaped slots including longitudinal portions adapted to register with the slots of said casing and to receive the ends of said pins, and including transverse portions into which the ends of said pins may be locked when said sleeve is rotated, for locking the claw in. a fixed position relative to the casing.

9. A climber as denned in claim 8, wherein saidcasing has a lower portion of reduced diameter providing an external bearing surface for said locking sleeve, has a shoulder dened at the upper extremity of said reduced portion, engaged by the upper end of said locking sleeve for transmitting load from said casing to said claw; said casing being provided with a collar threaded into its lower end and having a ilange extending radially and providing a bearing abutment for the lower endof said locking sleeve, said claw extending through said collar.

10. A climber as defined in claim 7, wherein said casing has in its lower portion an internal shoulder against which said striker may engage so as to limit the downward movement thereof, said abutment pin being projected above said shoulder in the fully loaded position of the climber.

11. In a linesmans climber, an elongated casing, means for attaching the same to a linesmans shoe, a claw having a shaft extending into said casing and having an abutment member, an annular striker encircling said shaft and slideable longitudinally within said casing and along said shaft for engagement against said abutment member, a spring under compression between the upper end of said striker and the upper end of said casing, for driving said striker downwardly relative to said shaft, said striker having a plurality of upwardly opening slots in its upper portion, a corresponding number of triggers each received within a respective slot and pivotally connected to said striker at its upper end, for lateral swinging movement of its lower end, said shaft having shoulder means against which the lower ends of said triggersmay engage when swung inwardly, in order that said striker may be supported upon said shaft while said casing is moveddownwardly under the weight of a linesman, whereby to load said spring, means yieldingly urging said triggers inwardly, and means carried by the upper end of said casing and rendered operative by the arrival of the casing at a downward limit of movement relative to said shaft, to release said triggers from their engagement with said shaft and thereby cause the striker to .be propelled downwardly by the loaded spring and to strike a blow against said abutment member, whereby to drive said claw into a body engaged thereby,

12. A climber as dened in claim 11, wherein said means forv urging said pawls inwardly comprises a split ring spring, and wherein said pawls have in their outer sides, notches in which said ring is engaged, said striker having an internal annular groove receiving said ring spring.

13. In a linesmans climber, an elongated casing having means for securing the same to a linesmans shoe, an abutment collar threaded into the upper end of said casing and adjustable longitudinally in the casing when rotated, a bearing bushing threaded through said collar and adjustable longitudinally of the casing when rotated therein, a claw having a shaft extending into said casing and having an abutment member, said shaft having a stem projecting from its upper end into said bushing and slideable therein, said shaft having a shoulder defined at the base of said stem, an annular striker encircling said shaft and slideable longitudinally within said casing for engagement against said abutment member, a coil spring under compression between the upper end of said striker and said abutment collar, for driving said striker downwardly relative to said shaft, trigger means for establishing a loading connection between said striker and said striker and said shaft whereby said striker may be supported upon said shaft while said casing is moved downwardly under the weight of a linesman, compressing said coil spring, resilient means yieldingly biasing said trigger means for establishing said loading connection at the downward limit of movement of said casing relative to said shaft, a tubular releasing plunger constituting a downward extension oi said bushing, engageable against said shoulder at the said lower limit of movement of the casing relative to the shaft, to provide a positive load transmitting connection between the casing and the shaft, and to establish said downward limit of movement of the casing, said releasing plunger being engageable with said trigger means as it approaches said downward limit and operative by said engagement to release said loading connection whereby said striker may be propelled downwardly by said spring to strike a blow against said abutment means for driving said claw into a body engaged thereby, and a relatively light coil spring received between said stem and said tubular releasing member, engaged under compression between said bearing bushing and said shoulder, for moving said shaft downwardly relative to said casing when the casing is lifted.

14. A climber as defined in claim 13, wherein said trigger means comprises a plurality of trigger members each pivoted at its upper end to said striker, and each having its lower end adapted to engage against said shoulder to establish said loading connection, said resilient means acting upon said trigger elements to urge them inwardly toward engagement with said shoulder, said trigger elements being inclined inwardly at the lower ends when thus engaged against said shoulder, and said tubular releasing member having a wedging engagement against the inclined inner side of said trigger elements to spread them apart for releasing said loading connection.

ROLAND A. MERRILL.

REFERENCES CITED The following references are of record in the 'rlle of this patent:

UNITED STATES PATENTS Number Name Date 1,572,046 Seiler Feb. 9, 1926 1,774,615 Rose Sept. 2, 1930 2,455,270 Ravella Nov; 30,-' 1948 2,460,113 Young Jan. 25, 1949

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