Patent Document

FIELD OF THE INVENTION  
       [0001]     This invention is related generally to cable-pulling devices and, more particularly, to power-assisted cable-pulling devices.  
       BACKGROUND OF THE INVENTION  
       [0002]     One of the duties of a lineman is pulling large wire cables. Currently, a lineman attaches a press device to the cable to be pulled. The press device is in turn attached to a line hook. The line hook is then attached to the hoist hook of a hoist.  
         [0003]     In some instances, truck-mounted or truck-pulled, trailer-mounted winches are appropriate for pulling the cable. In such instances, trucks have to have accessibility to the area where the pulling is to occur. Thus, in the first instance, such truck-mounted winches are unavailable for off-road or aerial use. Moreover, it is costly to outfit a truck with such a winch for general maintenance use. Further, such truck-mounted winches occupy much-needed storage space for other maintenance equipment. An example of such a trailer-mounted winch is illustrated in U.S. Pat. No. 5,388,781 (issued to Sauber).  
         [0004]     More frequently than truck-mounted winches, portable ratchet hoists are used by linemen. Examples of portable, manual, ratchet-type hoists are made by Coffing® (a division of Yale Industrial Products, Inc.), AB Chance (a division of Hubbell® Power Systems), or Maasdam Pow&#39;R-Pull, Inc. Such manual hoists have a hoist hook and a fixing hook. The fixing hook is attached to a fixture, such as a pole or tree. The hoist hook is attached to the hoist by a chain. Once the hoist hook and fixing hook are attached to the line hook and fixture, respectively, slack is taken out of the line through a lever action applied to a ratchet rotating the chain take-up wheel.  
         [0005]     In order to drive the ratchet, a lineman uses his or her arm, preferably driving the lever with proper body mechanics on each stroke. Use of the ratchet has resulted in chronic motion injury such as “tennis elbow” (also known as lateral epicondylitis), rotator cuff tears, shoulder strains, and tendinitis. These injuries are well known in the industry.  
         [0006]     A portable, powered line-pulling apparatus facilitating easy and safe cable pulling would be an important improvement in the art.  
       OBJECTS OF THE INVENTION  
       [0007]     It is an object of the invention to provide an improved cable-pulling device overcoming some of the problems and shortcomings of the prior art, including those referred to above.  
         [0008]     Another object of the invention is to provide a cable-pulling device that provides ease of operation.  
         [0009]     Another object of the invention is to provide a cable-pulling device that is portable by a person into areas that are inaccessible to trucks.  
         [0010]     Still another object of the invention is to provide a cable-pulling device that diminishes the possibility of repetitive stress injuries for linemen.  
         [0011]     Yet another object of the invention is to provide a powered cable-pulling device that is inexpensive.  
         [0012]     Another object of the invention is to provide a cable-pulling device that can be operated with minimal addition training over that provided to linemen using manual hoists to pull cable.  
         [0013]     How these and other objects are accomplished will become apparent from the following descriptions and the drawings.  
       SUMMARY OF THE INVENTION  
       [0014]     The invention involves a hand held, power-assisted cable-pulling apparatus. The hand held, power-assisted cable-pulling apparatus has a housing, a disc-like take-up wheel, a drive transfer coupling, at least one ratchet-portion-engageable dog pawl, a line, and a ground fixation mechanism. The housing has a hollow handle body within which is a fluid-powered actuator, a fluid control valve, for controlling fluid pressure supply to the actuator, and an operating trigger for the control valve. When used herein, the term “fluid” includes all non-solid substances, including liquids and gasses. The disc-like take-up wheel has a circumferential line-engaging portion and a concentric ratchet portion. The take-up wheel rotates about a take-up wheel shaft, which extends through the center of the take-up wheel. The shaft has a longitudinal axis about which the take-up wheel rotates. The take-up wheel shaft is attached with respect to the housing. The drive transfer coupling maintains an operative driving connection between the actuator and the ratchet portion. Further, there is at least one ratchet-portion-engageable dog pawl pivotally attached with respect to the housing. There is also a line having a cable attachment mechanism and non-slippingly engaged with the take-up-wheel line-engaging portion. The ground fixation mechanism is attached with respect to the housing for maintaining the housing fixed in space while power-assisted cable-pulling apparatus is in operation. The take-up wheel may be selectively rotated in a clockwise take-up direction.  
         [0015]     In certain embodiments, it is advantageous for the ground fixation mechanism to include a fixation-mechanism hook. In certain of these embodiments, it is even more advantageous for the fixation-mechanism hook to be configured to be able to rotate about the fixation-mechanism-hook axis. In this way, the fixation-mechanism hook may rotate in space while the housing remains stationary relative to it.  
         [0016]     It is preferable in certain embodiments for the line to be a strap having two ends. It is preferable in certain applications of this embodiment for the first end of the strap to be fixedly attached to the take-up wheel.  
         [0017]     It is preferable in certain embodiments which use a strap to include a cable-attachment-mechanism hook. The cable-attachment-mechanism hook is attached with respect to the second end of the strap, and is configured to attach to the cable. In other versions, it is preferable to have at least two pulleys in contact with the strap, located between the first and second ends.  
         [0018]     In other preferred embodiments of the invention, the line has a plurality of links. In certain of these embodiments, the circumferential line-engaging portion further has a plurality of radiating, spoke-like chain-engaging nubs. The spoke-like chain-engaging nubs are configured and arranged to releasably interact with the links.  
         [0019]     This de-linking could be similar to the interaction as of a bicycle sprocket and a bicycle chain.  
         [0020]     In another embodiment of the invention, the drive transfer coupling has a ratchet-engaging drive pawl. In a specific version of the preferred embodiment, the drive-transfer coupling further has a transfer member located between the drive pawl and the actuator. The transfer member is pivotably attached with respect to the housing.  
         [0021]     In yet another embodiment of the invention, the fluid is a gas. In still another embodiment of the invention, the fluid is a liquid. In certain specific versions, the liquid is an oil. It is preferable in certain liquid-fluid version of the invention to further comprise an electrified pump in fluidic communication with the actuator.  
         [0022]     In another preferable embodiment, there is a spring mechanism located between the housing and the dog pawl. The spring mechanism is potentially biased to provide an engaging force to the dog pawl. The biasing allows the spring mechanism to hold the dog pawl in engagement with the ratchet in a manner resistive to counter-clockwise, anti-take-up rotation of the take-up wheel. It is more preferable in some applications of this embodiment to provide a dog pawl release for urging the dog pawl out of engagement with the ratchet. The release in these embodiments are typically user selective or user determined to allow for counter-clockwise, rotation of the take-up wheel. In this way, the chain, strap, or other line may be slackened.  
         [0023]     In another aspect of the invention, a power-assisted cable-pulling apparatus is provided. The power-assisted cable-pulling apparatus comprises a piston, a fluid-powered means acting on the piston, a take-up wheel, a take-up-wheel axle, a fixation means, and a line with a cable-attachment mechanism. The piston has a longitudinal dimension between its first end and its second end (the second end being contained within a piston housing). The fluid-powered means acts on the piston second end. Through the fluid-powered means, the user may selectively urge the piston in positive longitudinal motion (i.e., driving the piston). The take-up wheel and the axle are concentric. The take-up-wheel axle is attached with respect to the piston housing. The axle has an axis about which the take-up wheel rotates. The take-up wheel surrounds the axle. The take-up wheel has a line-engaging portion and a concentric ratchet portion. The take-up wheel is rotatably mounted with respect to a housing. It may be placed on an axle that fits in a groove or slot in the housing. The ratchet portion is in initial touching contact with piston first end. The ratchet portion is configured and arranged such that positive longitudinal motion of the piston induces a clockwise rotation of the take-up wheel about the axle axis. The a fixation means is attached with respect to the piston housing, for holding the apparatus in place while in operation. The line has a cable-attachment mechanism, attached with respect to the take-up wheel. The cable-attachment mechanism is configured and arranged to spool about the line-engaging portion of the take-up wheel when the take-up wheel is rotated in a clockwise direction.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a perspective view of a preferred embodiment of the invention.  
         [0025]      FIG. 2  is a top sectional view of the embodiment of  FIG. 1  taken along line  2 - 2  of  FIG. 1 .  
         [0026]      FIG. 3  is a side, partial cut-away, sectional view of the embodiment of  FIG. 2  taken along line  3 - 3  of  FIG. 2 .  
         [0027]      FIG. 4A  is a schematic view of the power system in a first operational position.  
         [0028]      FIG. 4B  is a schematic view of the power system of  FIG. 4A  in a second operational position.  
         [0029]      FIG. 5A  is a schematic view of an alternate embodiment of the power system in a first operational position.  
         [0030]      FIG. 5B  is a schematic view of the power system mechanism of  FIG. 5A  in a second operational position.  
         [0031]      FIG. 6  is a perspective view of the invention in operation.  
         [0032]      FIG. 7  is a sectional cut-away side view of an alternate embodiment of the invention.  
         [0033]      FIG. 8  is a sectional cut-away side view of an alternate embodiment of the take-up wheel. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0034]     As seen in  FIGS. 1 and 6 , a cable-pulling apparatus  10  is configured to pull a cable  12 . Cable-pulling apparatus  10  has a housing  14 . Housing  14  is comprised of right housing portion  16  and left housing portion  18 . Right and left handle housing portions  16 ,  18  are attached together by means of machine screws  20  with machine screw heads  22 . Machine screws  20  extend through screw port  24  in right housing portion  16  where they are tightened into threaded machine screw receptors  26  (best seen in  FIGS. 2 and 3 ). Extending out from trigger aperture  28  formed at the juncture of forward portion  30  of connected right and left housing portions  16 ,  18  is trigger  32 . Provided also is trigger lock  33  for selectively maintaining trigger  32  in an “on” position. As seen in  FIG. 3 , trigger  32  is linked by linkage  34  to motor  36  (seen in  FIG. 4A ) which is powered by battery pack  37 . Switch motor  36  is electrically linked by wires  38  to a positive displacement pump  40 . Positive displacement pump  40  is of any suitable type, including vane and fan type displacement pumps. Displacement pump  40  is fluidically linked to oil reservoir bladder  42  by pump source tube  43  (which may include check valves).  
         [0035]     Extending out from positive displacement pump  40  is tube  44 . Tube  44  is in fluidic communication with three-valve solenoid  46 . Also in fluidic communication with three-valve solenoid  46  is chamber tube  48 .  
         [0036]     As seen in  FIGS. 4A, 4B , three-valve solenoid  46  has two positions. When in the first position illustrated in  FIG. 4A , oil from oil reservoir bladder  42  may be pumped by positive displacement pump  40  through solenoid supply tube  44 , through three-valve solenoid  46 , and thence through chamber tube  48  into piston chamber  50  under pressure. Piston chamber  50  is at the base of piston cylinder  54 . Within piston cylinder  54  is piston  56 . Piston  56  is made up of a piston head  58  and piston rod  60 . Piston-head face  62  forms the ceiling of the piston chamber  50 .  
         [0037]     On the interior surface  64  of piston cylinder  54  are lower and upper switches  66 ,  68  respectively. Lower and upper switches  66 ,  68  are in electrical communication with three-valve solenoid  46  through switch wires  69 .  
         [0038]     As seen in  FIG. 4B , when in the second position, three-valve solenoid  46  is also in fluidic communication with piston chamber  50  through chamber drain tube  70 . Extending out of three-valve solenoid  46  is recirculating tube  74 . Three-valve solenoid  46  is configured such that when three-valve solenoid  46  is in the second position, fluidic communication between pump  40  chamber tube  48  is interrupted and fluidic communication between positive displacement pump  40  and oil reservoir bladder  42  through recirculating tube  74  is enabled. Moreover, when three-valve solenoid  46  is in the second position, chamber tube  48  and chamber drain tube  70  are in fluidic communication such that any oil in piston chamber  50  may return to oil reservoir bladder  42 . Return of oil to reservoir bladder  42  is facilitated by the vacuum initially created in bladder  42  by pump  40  when the solenoid is in the first position, and is also facilitated piston spring  75 , which is biased in a down-stroke piston direction.  
         [0039]     As seen in  FIG. 3 , attached to housing is pivot  76 . L-shaped translation arm  78  is pivotably attached to pivot  76 . L-shaped translation arm  78  has a piston end  80  and a ram end  82 . Piston end  80  is configured to receive strikes from a top end  84  of piston rod  60 . It will be noted here that the words “top”, “bottom”, “up”, “down”, “base”, “horizontal”, “vertical” are all used with reference to the diagrams for ease of understanding. It will be readily seen that the unit may be operated in any direction and in any orientation such that what is described as “up” for purposes of this description may actually be downward toward the earth in operation of the unit in certain applications. Moreover, what will be described in terms of “clockwise” and “counter-clockwise”, are intended to refer to opposite directions of rotations; obviously what is considered “clockwise” is dependent on perspective and use of such terms herein is not limiting to particular perspectives illustrated.  
         [0040]     As top end  84  is driven upwardly to engage piston end  80 , rotation is introduced to translation arm  78  such that the upwardly driven motion is translated in a horizontal matter as ram end  82  interacts with piston end  86  of ram piston  88 . Ratchet end  89  of ram piston  88  interacts with drive sprocket teeth  90  on ratchet wheel  91  which is integral and concentric with take-up wheel  92 . Take-up wheel  92  rotates about wheel pivot  94 . Wheel pivot  94  is attached to right housing portion  16 . Together with left housing portion  18 , right housing portion  16  generally encloses take-up wheel  92 . Such enclosure is beneficial for multiple reasons, including four the safety of the operator, and the protection of the unit from external instrumentalities and dirt.  
         [0041]     Take-up wheel  92  is driven in a clockwise direction by the action of ram piston  88 . In forward operation, counter-clockwise rotation of take-up wheel  92  is prohibited by dog pawls  102 . In a fashion well known in the industry, dog pawls  102  rotate into engagement about pawl access  104 . Dog pawls  102  are biased into engagement with ratchet teeth  90  by pawl springs  106 . As also well known in the ratchet tool industry, ratchet may be selectively released in a counter-clockwise direction (e.g., see U.S. Pat. No. 6,805,028 issued to Chang). Reversibility is selected by reversing switch  108 .  
         [0042]     Take-up  92  has a circular, disk-like chain-take-up portion  110  concentric with the ratchet portion wheel  91 . Around perimeter of chain-take-up portion  110  are radically-extending chain teeth  112 . Chain teeth  112  encounter chain  114 .  
         [0043]     Integral with right housing portion  16  is tail-hook  116 .  
         [0044]     Use of the three-valve solenoid  46  allows for positive displacement pump  40  to remain in continuous operation while trigger  32  is depressed. An alternative hydraulic system is schematically illustrated in  FIGS. 5A and 5B . As with the three-valve solenoid  46 , two-valve solenoid  130  has two positions. When in the first position illustrated in  FIG. 5A , oil from oil reservoir bladder  42  may be pumped by positive displacement pump  40  through solenoid supply tube  44 , through two-valve solenoid  130 , and thence through chamber tube  48  into piston chamber  50  under pressure.  
         [0045]     As seen in  FIG. 5B , when in the second position, two-valve solenoid  130  is also in fluidic communication with piston chamber  50  through chamber drain tube  70 . Two-valve solenoid  130  is configured such that when two-valve solenoid  130  is in the second position, chamber tube  48  and chamber drain tube  70  are in fluidic communication such that any oil in piston chamber  50  may return to oil reservoir bladder  42 . As with the prior embodiment, return is facilitated both by the vacuum in bladder  42  created by pump  40  when in the first position and by piston spring  75 .  
         [0046]     It will be readily observed in the relevant hydraulics area that check valves (e.g., in pump source tube  43 ) and relief valves (e.g., in supply tube  44 ) will be engineered for safe and efficient operation of the hydraulic system.  
         [0047]     In the hydraulic systems when activated by trigger  32 , oil is pulled from bladder  42  into piston chamber  50  driving piston  56 . Piston  56  indirectly drives ram  88 . Ram  88  drives ratchet  90  rotating take-up wheel  92 . Rotating take-up wheel  92  draws chain  114  by means of teeth  112 .  
         [0048]     As piston  56  reaches apex point remote from the cylinder base, piston head  58  trips upper switch  68 . Upper switch  68  causes emptying of chamber  50  by movement of solenoid from first position (illustrated respectively in  FIGS. 4A, 5A ) to the second position (illustrated in  FIGS. 4B, 5B  respectively). As piston head  58  reaches nadir within chamber  50 , piston head  58  trips lower switch  66  causing pump to refill chamber  50  by switching solenoid from second position (illustrated in  FIGS. 4B, 5B ) to the first position (illustrated in  FIGS. 4A, 5A , respectively). Refilling piston chamber  50  with oil redrives piston  58 , thereby indirectly rotating take-up wheel  92 , further drawing chain  114 .  
         [0049]     As illustrated in  FIG. 7 , the system may also operate pneumatically. As illustrated in  FIG. 7 , trigger  32  is linked by linkage rod  34  to actuator  150 . Actuator  150  causes compressed gas (from an external gas source (such as a compressor or cartridge) not shown) through gas inlet channel  154  and chamber supply channel  156  into piston chamber  50  forcing piston  56  to drive ram  88  through translation arm  78  to in turn drive ratchet wheel  91 . In a similar manner to the pneumatic system, piston spring  75  allows for return of piston to its nadir position (thereby decreasing volume of piston chamber  50 ) when air is evacuated through chamber supply channel  156  and gas exit port  158  upon release of the trigger. Through multiple activations of trigger  32 , take-up chain  114  is incrementally pulled by take-up wheel  92  in a manner similar to that described above with regard to the hydraulic systems.  
         [0050]      FIG. 8  illustrates the use of a strap  160  as an alternative to a take-up chain  114 . Strap  160  is attached to take-up wheel  162  by means of insertion of strap first end portion  164  into fixing aperture  166 . Strap  160  is then reeled onto hub  168 . Take-up wheel  92  is driven by the ratchet  90  described above. Hub  168  and ratchet wheel  91  are concentric, each rotating about wheel pivot  94 . Two-pulley block-and-tackle  169  may be added for increased mechanical power.  
         [0051]     As seen in  FIG. 6 , in operation, unit  10  is affixed to a structure  170  (such as a tree, telephone pole, building, or truck). Attachment cable  172  is configured to firmly attach to fixture  170  in a manner not to come loose or break during the cable-drawing process. Fixation means  172  has a hook-receiving second end  174 . Hook  116  is attached to fixation means  172  at second end  174 .  
         [0052]     Attached to chain  114  is cable hook  174 , which in turn is hooked to cable fixation mechanism  176 . Cable fixation mechanism  176  is well known in the industry and firmly grips cable  12 . Once unit  10  is firmly affixed in its relative position between cable  12  and structure  170 , trigger  32  of unit is deployed by a user. Through continual ratcheting within unit  10 , chain  114  is drawn into unit  10  forcing cable  12  into motion toward fixture  172 .  
         [0053]     Once cable  12  has been moved position, the unit  10  is released. If under tension, cable  12  is first secured with respect to structure  172 ; if cable  12  is otherwise untensioned, cable  12  does not need to be secured. When cable  12  is secured in desired position, release mechanism  108  is deployed. Such release mechanisms to allow for back ratcheting are well described in the prior art.  
         [0054]     While the principles of the invention have been shown and described in connection with specific embodiments, it is to be understood that such embodiments are by way of example and are not limiting.

Technology Category: 7