CA1212926A - Wheel lift towing apparatus - Google Patents
Wheel lift towing apparatusInfo
- Publication number
- CA1212926A CA1212926A CA000491032A CA491032A CA1212926A CA 1212926 A CA1212926 A CA 1212926A CA 000491032 A CA000491032 A CA 000491032A CA 491032 A CA491032 A CA 491032A CA 1212926 A CA1212926 A CA 1212926A
- Authority
- CA
- Canada
- Prior art keywords
- lift
- tow
- wheel
- truck
- lifting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60P—VEHICLES ADAPTED FOR LOAD TRANSPORTATION OR TO TRANSPORT, TO CARRY, OR TO COMPRISE SPECIAL LOADS OR OBJECTS
- B60P3/00—Vehicles adapted to transport, to carry or to comprise special loads or objects
- B60P3/12—Vehicles adapted to transport, to carry or to comprise special loads or objects for salvaging damaged vehicles
- B60P3/125—Vehicles adapted to transport, to carry or to comprise special loads or objects for salvaging damaged vehicles by supporting only part of the vehicle, e.g. front- or rear-axle
Landscapes
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Public Health (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Handcart (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A vehicle wheel lift towing apparatus for mounting onto a rear portion of a tow truck is disclosed. The apparatus comprises a rigid lift beam with wheel lifts which are positionable beneath the disabled vehicle. The beam is pivotally connected to a lift which is vertically movable on a support secured to the rear of the tow truck. The lift is pivotally connected to the device which guides the vertical movement of the lift. The pivotal connections permits hinged movement of the lift beam towards the lift when the beam is swung onto a tow truck for storage. Such folding action of the towing apparatus provides compact storage and swinging movement of the beam beneath any obstructions on the tow truck, such as a tow sling arrangement.
A vehicle wheel lift towing apparatus for mounting onto a rear portion of a tow truck is disclosed. The apparatus comprises a rigid lift beam with wheel lifts which are positionable beneath the disabled vehicle. The beam is pivotally connected to a lift which is vertically movable on a support secured to the rear of the tow truck. The lift is pivotally connected to the device which guides the vertical movement of the lift. The pivotal connections permits hinged movement of the lift beam towards the lift when the beam is swung onto a tow truck for storage. Such folding action of the towing apparatus provides compact storage and swinging movement of the beam beneath any obstructions on the tow truck, such as a tow sling arrangement.
Description
. 1 WHEEL LIFT TOWING APPARATUS
FIELD OF T~E INVENTION
This invention relates to towing apparatus which, when mounted to a tow truck, is adapted to lift a disabled vehicle by its front or rear set of wheels.
BACKGROUND OF THE INVENTION
With a continuing effort by the automotive manufacturers to reduce the weight of vehicles and hence increase gas mileage, there has been a considerable reduction in the amount of metal used in bumper systems for cars and the manner in which they are secured to cars. Hence, vehicle towing devices, which rely in one manner or another on lifting the car either by the bumper or indirectly involving the bumper of the car, can cause considerable damage in lifting and towing to the disabled vehicle. A very popular type of vehicle lift system is commonly referred to as "the tow sling"~ The sling includes spaced-apart rubber belts which are secured to a device connected to the vehicle wheel axles. The rubber belts of the sling pass under the bumper towards a bar which is connected to the tow cable of the to~w truck boom. With the less rigid form of bumper on today's car, the bumper can be bent upwardly into the ~ront or rear grill of the car by the rubber belts of the tow sling resulting in damage to the bumper and grill system. This is particularly troublesome with compact cars and sports cars.
The tow truck industry has, therefore, moved to a system which lifts a vehicle by its wheels and does not in any way contact the bumper or adjacent area of the car. A variety of wheel lifts have, therefore, been developed in the marketplace, all of which offer in one form or another a fairly reliable system for lifting a vehicle by the wheels without damaging the disabled vehicle bumper system. An example of such a wheel lift system is disclosed in United States patent 3l434,607.
The system, which is positionable beneath the vehicle wheels for engaging and lifting same, is connected to the rear of a tow truck by a parallelogram linkage system.
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-~ 2 The truck winch is used to raise the vehicle wheel engaging device, whereby the parallelogram linkage maintains a particular desired slope to the wheel engaging device. Although this system may be satisfactory for a very small sub-compact car, with larger cars the parallelogram linkage is very susceptible to sway and bending which can considerably reduce or render useless the effectiveness of the towing device, thereby re~uiring repair or replacement.
Another type of wheel lift device mounted beneath the tow truck is disclosed in United States patent 3,690,482. A lift beam for the device is pivotally connected beneath the tow truck proximate the drive axleO
The boom hook is used to raise and lower the lift beam where at its extremity, wheel engaging devices are provided, It is appreciated that with new models available in the marketplace, such systems may be hydraulic controlled. The major drawback, however, is storage of the device since they either have to be retracted beneath the vehicle or remain extended of the rear of the vehicle, resulting in possible driving hazards. In an effort to make this type of system more compact to avoid the wheel left system projecting from the rear of the tow truck, the lift beam of the system may be pivotally mounted to the rear of the tow truck frame in the manner disclosed in United States patent 3,924,763. In providing for a storage position, the lift beam with wheel engaging devices as a unit is pivoted upwardly against the rear portion of the truck. ~Iowever this system requires that the truck be dedicated solely to that particular lift system and does not permit the use of combined tow systems on a sin~le tow truck.
Other types of systems, which involve the pivoting of the lift beam in one manner or another to the rear of the t~ow truck, are disclosed in United States patents 4,384,817 and 4,473,334. With both of these systems, the truck has to be dedicated to that particular unit. In United States patent 4,384,817, the lift beam is pivotally connected to a lift system. That lift system ~Z~9~i is in turn pivotally connec-ted to the bed of the tow truck forwardly of the rear axle. The lift system is raised by means of a power hoist hook. Because of its pivotal connection, the lift beam is tilted upwardly as the vehicle is raised to ensure that the lift beam clears the underside of the vehicle. When the system is not in use, the lift beam may be pivoted upwardly to a vertical position for storage against the xear of the tow truck.
A similar system is disclosed in ~nited States ~,473,334 where the lift device again is pivoted to the truck bed forwardly of the rear axle. The lift beam, which is positionable beneath the disabled vehicle, is pivotally connected to the lift system and may be moved to essentially vertical storage position against the rear of the truck~ Both of these systems are designed in a manner which precludes the mounting of any other forms of vehicle towing devices, such as the standard tow sling.
United States patent 4,451,193 provides a compact wheel lift arrangement having pivotal connection of the wheel lift to a slide adapted for vertical movement and which is connected to the rear of the tow truck. The lift beam is L-shaped with a secure interconnection of the beam portion which is positioned beneath the car to the upright beam portion which is pivotally connected to the slide. A linkage arrangement is required beneath the tow vehicle for interaction with the L-shaped beam to kick the L-shaped beam upwardly as the vehicle is raised.
This action of the linkage arrangement tilts the horizontal beam slightly upwardly to avoid contact with the disabled vehicle bumper systemD The lifking beam, as an integral unit, is swung upwardly and over onto the tow truck bed for purposes of storage. As a result no other form of towing device may be mounted to the rear of the tow truck, since this would preclude storage of the integral arrangement for the lift beam having permanently attached wheel lift engaging devices.
UMMARY OF THE INVENTION
According to an aspect of the invention, a vehicle wheel lift towing apparatus for mounting onto a rear ~2~Z~Z~
portion of a tow truck comprises a rigid lift beam for positioning beneath the disabled vehicle. Wheel lift means are provided to each side of and interconnected to the ~eam for engaging and lifting a set of disabled vehicle wheels. Beam lift means is adapted for vertical lifting movement when in use on a tow truck. Means is provided for mounting the beam lift means to a rear portion of the tow truck. The mounting means is adapted to provide for vertical travel of the lift means from a lower vehicle wheel lifting position to an upper vehicle towing position. The lift means includes a downwardly depending arm. A first end of the depending arm is pivotally connected to the mounting means. A first end of the lift beam is pivotally connected to a lower portion of the depending arm. Means is provided for limiting downward swinging move~lent of the lift beam xelative to the lift means to define a wheel lift position for the lift beam. The pivotal connection of the lift beam to the lift means permits hinged movement of the lift beam towards the lift means when the lift beam is swung onto a tow truck for storage of the lift beam.
According to another aspect of the invention, means is provided for releasably interconnecting the wheel lift means to each siae of the lift beam. The wheel lift means are removable from the lift beam prior to swinging the beam to a storage position on a tow truck.
According to a further aspect of the invention, the mounting means for securing the lift means to the tow truck comprises a carriage and track. The carriage is engaged with the track for vertical movement of the carriage. The first end of the lift means is pivotally connected to the carriage.
According to a preferred aspect of the invention, the pivotal arrangement for the connection of the lift beam to the lift means and the lift means to the carriage of the tow truck is such to permit swinging of the lift beam beneath a yoke or the like of a tow sling already mounted on a tow truck. This facilitates storage of the ~,...
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lift beam beneath the tow sling on the bed of a tow truck.
BRIEF DESCRIPTION_OF THE DRAWINGS
Preferred embodiments of the invention are shown in S the drawings wherein:
Figure 1 is a perspective view of the rear portion of a tow truck showing a sling tow system and a wheel lift tow system both connected to the -truck;
Figure 2 illustrates the folding action of the wheel lift system in either removal from or return to the storage position;
Figures 3, 4 and 5 are side elevation views of the tow truck of Figure 1 (the tow sling removed for sake of clarity in illustration) and illustrating in sequence removal of the wheel lift system from the tow truck bed;
Figure 6 is a side elevation o~ the tow truck of Figure 3 with the wheel lift positioned in readiness to be placed ~eneath the disabled vehicle;
Figure 7 is a bottom view of the tow lift system of
FIELD OF T~E INVENTION
This invention relates to towing apparatus which, when mounted to a tow truck, is adapted to lift a disabled vehicle by its front or rear set of wheels.
BACKGROUND OF THE INVENTION
With a continuing effort by the automotive manufacturers to reduce the weight of vehicles and hence increase gas mileage, there has been a considerable reduction in the amount of metal used in bumper systems for cars and the manner in which they are secured to cars. Hence, vehicle towing devices, which rely in one manner or another on lifting the car either by the bumper or indirectly involving the bumper of the car, can cause considerable damage in lifting and towing to the disabled vehicle. A very popular type of vehicle lift system is commonly referred to as "the tow sling"~ The sling includes spaced-apart rubber belts which are secured to a device connected to the vehicle wheel axles. The rubber belts of the sling pass under the bumper towards a bar which is connected to the tow cable of the to~w truck boom. With the less rigid form of bumper on today's car, the bumper can be bent upwardly into the ~ront or rear grill of the car by the rubber belts of the tow sling resulting in damage to the bumper and grill system. This is particularly troublesome with compact cars and sports cars.
The tow truck industry has, therefore, moved to a system which lifts a vehicle by its wheels and does not in any way contact the bumper or adjacent area of the car. A variety of wheel lifts have, therefore, been developed in the marketplace, all of which offer in one form or another a fairly reliable system for lifting a vehicle by the wheels without damaging the disabled vehicle bumper system. An example of such a wheel lift system is disclosed in United States patent 3l434,607.
The system, which is positionable beneath the vehicle wheels for engaging and lifting same, is connected to the rear of a tow truck by a parallelogram linkage system.
g~
-~ 2 The truck winch is used to raise the vehicle wheel engaging device, whereby the parallelogram linkage maintains a particular desired slope to the wheel engaging device. Although this system may be satisfactory for a very small sub-compact car, with larger cars the parallelogram linkage is very susceptible to sway and bending which can considerably reduce or render useless the effectiveness of the towing device, thereby re~uiring repair or replacement.
Another type of wheel lift device mounted beneath the tow truck is disclosed in United States patent 3,690,482. A lift beam for the device is pivotally connected beneath the tow truck proximate the drive axleO
The boom hook is used to raise and lower the lift beam where at its extremity, wheel engaging devices are provided, It is appreciated that with new models available in the marketplace, such systems may be hydraulic controlled. The major drawback, however, is storage of the device since they either have to be retracted beneath the vehicle or remain extended of the rear of the vehicle, resulting in possible driving hazards. In an effort to make this type of system more compact to avoid the wheel left system projecting from the rear of the tow truck, the lift beam of the system may be pivotally mounted to the rear of the tow truck frame in the manner disclosed in United States patent 3,924,763. In providing for a storage position, the lift beam with wheel engaging devices as a unit is pivoted upwardly against the rear portion of the truck. ~Iowever this system requires that the truck be dedicated solely to that particular lift system and does not permit the use of combined tow systems on a sin~le tow truck.
Other types of systems, which involve the pivoting of the lift beam in one manner or another to the rear of the t~ow truck, are disclosed in United States patents 4,384,817 and 4,473,334. With both of these systems, the truck has to be dedicated to that particular unit. In United States patent 4,384,817, the lift beam is pivotally connected to a lift system. That lift system ~Z~9~i is in turn pivotally connec-ted to the bed of the tow truck forwardly of the rear axle. The lift system is raised by means of a power hoist hook. Because of its pivotal connection, the lift beam is tilted upwardly as the vehicle is raised to ensure that the lift beam clears the underside of the vehicle. When the system is not in use, the lift beam may be pivoted upwardly to a vertical position for storage against the xear of the tow truck.
A similar system is disclosed in ~nited States ~,473,334 where the lift device again is pivoted to the truck bed forwardly of the rear axle. The lift beam, which is positionable beneath the disabled vehicle, is pivotally connected to the lift system and may be moved to essentially vertical storage position against the rear of the truck~ Both of these systems are designed in a manner which precludes the mounting of any other forms of vehicle towing devices, such as the standard tow sling.
United States patent 4,451,193 provides a compact wheel lift arrangement having pivotal connection of the wheel lift to a slide adapted for vertical movement and which is connected to the rear of the tow truck. The lift beam is L-shaped with a secure interconnection of the beam portion which is positioned beneath the car to the upright beam portion which is pivotally connected to the slide. A linkage arrangement is required beneath the tow vehicle for interaction with the L-shaped beam to kick the L-shaped beam upwardly as the vehicle is raised.
This action of the linkage arrangement tilts the horizontal beam slightly upwardly to avoid contact with the disabled vehicle bumper systemD The lifking beam, as an integral unit, is swung upwardly and over onto the tow truck bed for purposes of storage. As a result no other form of towing device may be mounted to the rear of the tow truck, since this would preclude storage of the integral arrangement for the lift beam having permanently attached wheel lift engaging devices.
UMMARY OF THE INVENTION
According to an aspect of the invention, a vehicle wheel lift towing apparatus for mounting onto a rear ~2~Z~Z~
portion of a tow truck comprises a rigid lift beam for positioning beneath the disabled vehicle. Wheel lift means are provided to each side of and interconnected to the ~eam for engaging and lifting a set of disabled vehicle wheels. Beam lift means is adapted for vertical lifting movement when in use on a tow truck. Means is provided for mounting the beam lift means to a rear portion of the tow truck. The mounting means is adapted to provide for vertical travel of the lift means from a lower vehicle wheel lifting position to an upper vehicle towing position. The lift means includes a downwardly depending arm. A first end of the depending arm is pivotally connected to the mounting means. A first end of the lift beam is pivotally connected to a lower portion of the depending arm. Means is provided for limiting downward swinging move~lent of the lift beam xelative to the lift means to define a wheel lift position for the lift beam. The pivotal connection of the lift beam to the lift means permits hinged movement of the lift beam towards the lift means when the lift beam is swung onto a tow truck for storage of the lift beam.
According to another aspect of the invention, means is provided for releasably interconnecting the wheel lift means to each siae of the lift beam. The wheel lift means are removable from the lift beam prior to swinging the beam to a storage position on a tow truck.
According to a further aspect of the invention, the mounting means for securing the lift means to the tow truck comprises a carriage and track. The carriage is engaged with the track for vertical movement of the carriage. The first end of the lift means is pivotally connected to the carriage.
According to a preferred aspect of the invention, the pivotal arrangement for the connection of the lift beam to the lift means and the lift means to the carriage of the tow truck is such to permit swinging of the lift beam beneath a yoke or the like of a tow sling already mounted on a tow truck. This facilitates storage of the ~,...
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lift beam beneath the tow sling on the bed of a tow truck.
BRIEF DESCRIPTION_OF THE DRAWINGS
Preferred embodiments of the invention are shown in S the drawings wherein:
Figure 1 is a perspective view of the rear portion of a tow truck showing a sling tow system and a wheel lift tow system both connected to the -truck;
Figure 2 illustrates the folding action of the wheel lift system in either removal from or return to the storage position;
Figures 3, 4 and 5 are side elevation views of the tow truck of Figure 1 (the tow sling removed for sake of clarity in illustration) and illustrating in sequence removal of the wheel lift system from the tow truck bed;
Figure 6 is a side elevation o~ the tow truck of Figure 3 with the wheel lift positioned in readiness to be placed ~eneath the disabled vehicle;
Figure 7 is a bottom view of the tow lift system of
2~ Figure 6 placed beneath the front set of wheels of the disabled ~ehicle;
Figure 8 is a perspective view of the wheel lift system as assembled and readied for attachment to the rear gate or truck back of a tow truck;
Figure 9 is a perspective view of the upper portion of the wheel lift system of Figure 8 showing locking of the whee~ lift in the storage position on a tow truck bed;
Figures 10 and 11 show in sequence the lifting of a disabled vehicle; and Figure 12 is an exploded view of components of the wheel lift system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A tow truck generally designated 10, as shown in Figure ~, has a flat bed 12 with rear gate or truck back 14. Two towing systems are provided on the tow truck 10.
The first tow system is the standard well known type of tow sling generally designated 16 and the second towing ~z~
system is a whe~l lift system generally designated 18 according to a preferred embodiment of this invention.
The standard type of tow sling 16 comprises a tow bar 18 connected to the first end portions 20 and 22 of the belted sling 24. The two reinforced rubber belts 26 and 28 extend from the tow bar 19 upwardly and are connected to a sling lift member 30 at their second ends 32 and 3~. The lift bar 30 has a clevice 36 to which a hoist chain 38 or hook may be connected to raise and lower the tow sling. The tow bar 18 is pivotally connected to the gate 14 of the tow truck by a tow sling yoke 40. The yoke 40 comprises two arms 42 and 44. The first ends 46 and 48 of the respective arms are pivotally connected at 50 and 52 to the rear gate by appropriate hinge structures 54 and 56. The second ends 58 and 60 of the arms are pivotally connected to a hinge bracket 62 which, in turn, is secured to the tow bar 18. The yoke 40 is shown in its stowed position. Although not shown, an appropriate loc~ing device may be provided to lock the yoke in its substantially vertical stowed position.
According to this invention, the wheel lift system 18 is arranged to permit storage and removal of the lift system to and from the tow truck flat bed 12 without having to remove the tow slin~. This invention, therefore, enables the use of two separate towing systems which are mutually compatible, in that the tow sling is useful in a variety of situations including disabled vehicles which are severely damaged, whereas the wheel lift system can be used on vehicles which are disabled or have at least one set of wheels which permits towing of the vehicle by the wheels.
With reference to Figure 12, ~he details of the wheel lift are shown. The wheel lift comprises a lift beam 66 which, according to a preferred embodiment of 3S this inven~ion, consists of telescopic members 68 and 70.
Outer sleeve 6~ includes a collar 72 with a threaded aperture 74 through which a threaded locking bolt 76 is provided. The draw bar portion 70 includes three spaced-apart apertures 78, such that when the draw bar is ..~
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telescoped into the sleeve 68, the locking bolt 76 may be placed in one of the desired apertures 78 to provide various extented lengths for the lift beam 66. The lift beam may be formed of various grades of steel which have sufficient strength to resist the forces placed on the lift beam during use. The sleeve portion 68 may be formed of welded plate, whereas the draw bar 70 may be of solid steel or welded plate steel in a box structure.
The dimensioning of the draw bar 70 is such to ~e snugly received within the opening 80 of the sleeve 68.
The lift beam 66 is pivotally connected to a beam lifting device 82. The beam lifting device 82, in the form of a downwardly depending arm, comprises a tapered box structure having front and rear surfaces 84 and 86 and opposing side surfaces 88 and 90. The box structure may be formed of welded plates where the tapered construction is provided by tapered sides 88 and 90. To the lower end 92 of the beam lifting device 82 a first end 94 of the lift beam 66 is pivotally connected.
According to this preferred embodiment, two generally triangular-shaped plates 96 and 98 are welded to the side portions 100 and 102 of the sleeve 68. The plates 96 and 98 include aligned apertures 104 and 106 which can be placed into register with apertures 108 and 11~. A bolt 112 and lock nut 114 complete the pivotal connection in the form of a hinge arrangement of the plates 96 and 98 to the lower end 92 of the lifting device 82. The positioning of the apertures 104 and 106 in the plates 96 and 98 is such to ensure that the first end 94 abuts the lower portion of the front face ~4 when the lift beam is in the towing position. Hence, the first end 94 abutting the front face 84 of the lift device acts as a stop or device for limiting the exten~ to which the lift beam 66 may pivot downwardly or swing downwardly relative to the lifting device 82.
The beam lift device 82 is pivotally connected at its upper end 116 to a mounting system which interconnects the lifting device to the rear of a tow truck. Such mounting system is adapted to provide for vertical movement of the lift device 82. According to z~
this preferred embodiment, the mounting device includes a carriage 118 which is engaged with a track 120 for riding upwardly and downwardly within the track system 120 The upper portion 116 of the lifting device 82 is pivotally S connected to opposing plate portions 122 and 124 of the carriage 118. Apertures 126 extending through the side walls 88 and 90 are registered with the apertures 128 and 130 in the opposing plates 122 and 124. A bolt 132 and lock nut 134 are used to pivotally interconnect the upper end li6 of the lifting device to the carriage arms 122 and 124. The carriage arms also include two sets of rollers 136 and 138. The rollers are provided to each side of the carriage and are placed within the opposing track channels 140 and 142. The rollers 136 and 138 are secured to axles which in turn are mounted in greased bushings secured to plates 122 and 124. It is appreciated that all types of mounting for the rollers are acceptable, howQver, the bushings provide the most support.
The track channels 140 and 142 are dimensioned to receive the rollers sets 136 and 138 in a manner which captures the rollers and minimizes rocking of the carriage as it rides upwardly and downwardly within the track. At the base of the mounting system 119, are two spaced-apart rollers 144 and 146. These rollers are mounted on an axle 149 which is mounted in greased bushings connected to opposing side walls 150 o the opposing track portions of the track system 120 and to the central portion of the rear plate 148 (not shown).
Rollers 144 and 146 engage the rear face 86 of the lifting device to tilt the lifting device as it is raised over the rollers 144 and 146, the purpose of which is to be explained with respect to Figur~s 10 and 11. The U-shaped tracks 140 and 142 are secured to a rear plate 148 which, in turn, is bolted or welded to the gate of the tow truck. If bolted, apertures 151 may be used. It is appreciated that on either bolting and/or welding the plate 140 to the tow truck gate, sufficient bolts and welds must be used to ensure a permanent secure ~2~6 g connection to withstand the loads placed on the wheel lifting device.
Secured to U-shaped track outer face 152 is a spring loaded locking bolt 154 which is used to lock the carriage in the uppermost load carrying position by engaging aperture 156 in plate 124 of the carriage 118.
Secondly, the locking bolt 154, upon engaging aperture 158 in plate 98 of the lift beam, with the lift beam in stored position on the bed of the truck, locks the lifting beam in the storage position so that it cannot swing out while travelling.
To complete the wheel lift system, the wheel lift devices for engaging the wheels and lifting same are pivotally connected to end 160 of the draw bar 70. A
swivel 162 comprising a hollow rectangular sleeve has secured thereto opposing plates 15~ and 166. The plates include opposing apertures 168 and 170 which are in register with aperture 172 extending through the end 160 of the draw bar 70. A bolt 174 with a nut 176 having a "Nylon" lock is used to complete the pivotal interconnection of the sleeve 162 to the draw bar. Each end of the sleeve includes a rectangular-shaped opening 178 to receive a corresponding rectangular-shaped bar 180 of each wheel lift device 182 which is shown and described in more detail with respect to Figure 8. The bar 180 of each wheel lift device may be inserted through the opening 178 to within the hollow sleeve 162 in the direction of arrow 184. When the wheel lift device is engaged with a vehicle wheel and the beam is lifted, the frictional engagement of the rod 180 within the sleeve 162 resists any sliding movement between the rod 180 and the sleeve 162 and, due to their mating interengagement, resists rotation relative to the lift beam to provide an upward lifting force on the vehicle wheels.
As shown in more detail in Figure 8 with respect to each wheel lifting device 182, it comprises spaced-apart arms 186 and 188. The arms are interconnection at their front portion by a continuation of the rod 180. Secured to the rear face of rod 180 is a wedged-shape plate 190 ~2~Z~;~6 ._. 10 to support a larger circumferential portion of the disabled vehicle wheel 192. Depending upon the size of the wheel, a rod 194 is dropped into respective opposing slots 196 and 198 of the arms 186 and 188 to capture an underside portion of the wheel, such that when the lift is raised, the wheel does not drop between the rod 194 and the wedge l9n to ensure lifting of the vehicle. As is appreciated by those skilled in the art, with this type of wheel lift, it is desirable to place the rod 194 in notches 196 and 198 closest to the wheel.
It is appreciated that the wheel lift system, as assembled in Figure 8, may be sold as a unit which can be attached to the gate of a used tow truck by the truck service operator. Although the unit can be assembled on a new tow truck as original equipment optionally in combination with some other types of tow devices, such as a tow sling. In mounting the plate 148 of the mounting device 119 to the tow truck gate, when the tow truck is already provided with another form of towing device, the rear gate or truck back of the truck, if not adequately supported, should include additional supports and struts to ensure that flexing in the gate is minimized when the wheel lift device is secured to the truck gate.
With the wheel lift system 18 properly secured to the truck gate 14 as shown in Figure Z, the lift beam 66 may be removed by the articulated movement of the lifting device 82 relative to the lifting beam 66. The lifting beam includes two eyes 200 and 202. The tow truck hook 204, as it engages eye 200 as shown in Figure 1, ~lay be used to raise the wheel lift beam 66 onto the tow truck bed 12 in the direction of arrow 206. Due to the articulated folding movement of the wheel lift system, the swivel 162 is permitted to pass beneath the bracket 62 o~ the yoke 40 of the tow sling. The geometry is such that with the carriage 118 in its lowermost position in tracX 120, the extremity of the lifting beam fits and slides smoothly beneath the yoke 40. Hence, the provision of the removable wheel lift devices 182 to leave thereby only the beam which moves through the opening of the yoke 40. In this manner, the invention provides for two vehicle lift systems on a tow truck body to permit lifting of practically all types of disabled road vehicles exclusive of the heavy tandem truck and S other comparable types of large industrial vehicles.
Once the lifting beam has been placed in the storage position on the tow truck bed, as already noted, it is important to ensure that the beam is secured in place so that during transport, it cannot shake loose and fall rearwardly of the tow truck. This may be accomplished by cables or use of the hooX 204 in drawing the lifting device 82 snugly against the rear of the tow truck vehicle. More conveniently, as shown in Figure 9, the releasable lock 15~ has a r~tractable bolt portion 206 for placement in the aperture 158 in plate 98. With the retractable bolt 206 positioned in the aperture 158, the lifting device 82 is held against the gate 14 of the tow truck. When it is desired to remove the liftiny beam from the tow truck bed, the retractable bolt 206 is withdrawn by use of handle 208. The handle 208 can be withdrawn and rotated to position the lug 210 against the exterior face 212 of the sleeve 214 and thereby hold the bolt 206 retracted clear of the aperture 158. Then by use of the tow truck hook 204 placed in eye 202 of the lifting beam, it may be withdrawn from the tow truck bed.
The sequence in removal of the lifting beam from the tow truck bed and the reverse Gf that sequence for placing it on the two truck bed is schematically shown in Figures 3 through 6. The tow truck 10 is equipped with a boom 216 which may be raised and lowered by way of h~draulic ram 218. It is appreciated that the boom may, however, be in the fixed position as held by a cable or the like. A power winch 220 is provided on the structure for the boom 216 to either pay out or reel in cable 222 to which the lifting hook 204 is secured. For purposes of demonstrating the sequence and use of the lifting beam, the second tow structure in the form of a sling has not been shown. To remove the lifting beam 66 from the tow truck bed, the hook 204 may be connected to either of eyes 200 or 202, depending upon the weight distribution in the beam. As shown in Figure 3, the hook 204 is connected to the eye 200 by pulling the lifting beam 66 rearwardly. Either manually or by slightly raising the hook 204, the lifting device may be swung rearwardly to the position shown in Fi~ure 4, The weight of the lifting device 82 in combination with the weight of the beam 66 will now cause the lifting beam to slide rearwardly as it folds against the lifting de~ice 82 until it assumes a position as shown in Figure 5. During this continued rearward movement of the lifting beam 66, its outermost end defined by the swivel connection 162 does not rise above the level indicated by arrow 224, which is the height of the tow bar bracket 62 of the tow sling 16.
During the unfolding action of the lifting device, the carriage 118 remains in its lowermost position in the track 120, such that when the lifting beam 66 is lowered to the ground as shown in Figure 6, the system is ready for lifting a disabled vehicle. The lowering of the beam 6~ to the ground may be either done manually or by repositoning the hook 204 in eye 202 and slowly paying out the cable 222 until the lifting beam 66 is proximate the ground level 226. At this time, the wheel engaging devices 182 are removed from the truck bed and their rectangular-shaped bar portions 180 inserted in the open ended sleeves 162 in preparation for positioning beneath a vehicle ~2~. It is appreciated the reverse of this movement retains the lifting beam 66 to its stowed position on the bed 14 of the tow truck.
The bars 18~ and 188 of the wheel engaging device 182 are sufficiently spaced apart so as to pass by each side of the disabled vehicle tire 230. The wheel engaging bax 194 is then positioned in each wheel engaging device so as to capture the tire between the bar 194 and the wedge 190. Straps or the like may be used to hold the wheels on the devices 182.
~ s shown in more detail in Figure 10, the disabled vehicle 228 is positioned in the wheel engaging devices 182 with the draw bar 70 secured in the outer sleeve 68 of the lifting beam 66 by the locking bolt 76. The sleeve 162 is secured at a slight angle relative to plates 164 and 166 of Figure 12 to locate the devices 182 at ground level with -the lifting arm 66 angled downwardly. The end portion 94 of the sleeve 68 abuts the front face 84 of the lifting device 82. Due to the pivotal connection of the plates 96 and 98 to the sides 88 and 90, the beam will not pivot any further downwardly relative to the lifting device 82. Hence, the first end 94 of the lifting beam 66 acts as a stop to limit the extent to which the lifting beam can swing downwardly relative to the lifting device 82. The carriage 118 is in its lowermost position as determined by paying out the cable 222 for the hook 204 as it engages the opening 232 in the front face 84 of the lifting device. The shape of the aperture 232 in the front face of the lifting device is shown in more detail in Figure 12. The rear face 86 of the lifting device 82 is in contact with the rollers 144, 146 which are secured to the lowermost portion of the track 120. By tapering the side faces 88 and 90 of the lifting device 82, the front face 84 of the lifting device is swung outwardly relative to the track 120 by its pi~otal connection at 126 to the carriage 118.
Upon raising of the tow hook 204 by reeling in the cable 222, the rear face 86, as it rides upwardly over the rollers 144, 146, pivots the lifting device 82 outwardly away from the track 120. This swings the lifting beam 66 upwardly relative to the track 120 to ensure that the lifting ~eam 66 does not interfere with the underside 234 of the disabled vehicle 228. In addition the angled relationship of the sleeve 162 to the plates 16~ and 166 prevents the devices 182 from sloping downwardly as the arm 66 is lifted. Any slack in the interconnections of arm 70 in sleeve 68 and at other joints in the lifting device are compensated for by the angle relationship of the sleeve 162 in the plates 164 and 166. Hence when a car is raised as shown in Figure 11, the devices 182 extend outwardly from the lifting arm Z~
in essentially the same plane. The engagement of the rollers 136 and 138 with the interface 236 of each track channel 1~0 and 142 captures the carriage 118 in its vertical movement from its lowermost to uppermost position. When the carriage 118 is in its uppermost position, the loc]c bolt 154 may be inserted in aperture 156 of the carriage, as shown in more detail in Figure 12, to lock the carriage in the uppermost position to provide an additional safety factor to ensure that the vehicle is not dropped during the towing process, should for example, the cable 222 break and release the hook 204.
The roller system for the carriage is of sturdy construction and preferably includes provisions for frequent greasing of the rollers. In addition, the rollers 144 and 146 are provided with greased fittings.
By forming the track channels 140 and 142 from sufficiently thick, high grade, steel plate, the forces of the set of rollers 136 and 138 are distributed over the innerfaces 236 of the tracks to prevent bending of the track interfaces. A solid construction is provided in pivoting the lifting device 82 to the carriage where the lifting device is supported on its rear face by the rollers 144 and 146. As explained with respect to Figure 11, such roller engagement not only provides for support of the lifting device in limiting the extent to which the lifting device pivots towards the track, but also provides for a kick out or pivoting of the lifting beam relative to the track to ensure that it clears the lower portion of the disabled vehicle when lifted. The pivoted connection of the lifting beam 66 to the lifting device 82, which includes means for limiting the extent of downward swinging of the beam, provides a folding action of the beam towards the lifting device to permit positioning of the beam onto the tow truck bed in ~n efficient compact manner, while taking up little space and preferably when used in combination with a tow sling, the free end of the lifting beam with the wheel engaging 2~
device removed slides beneath the inverted V-shaped yoke of the tow sling device~
As shown in Figures 10 and 11, the side portions 88 and 90 of Lhe lifting device 82 always remain within the opposing edges 141 and 143 as shown in Figure 12 due to the positioning of the rollers 144 and 146. This confinement of the side edges of the lifting device within the track minimizes the chance of sway of the lower portion of the lifting device relative to its pivotal connection to the carriage 118. To lend additional support in confining the sides of the lifting device, lugs 238 and ~40 are provided at the lower ends track edges 141 and 143. These lugs in combination with the opposing edges 141 and 143 of the track minimize the lateral movement of the lifting device during vertical travel of the carriage. This reduces torsion on the carriage device during the carrying of heavy loads and thereby providing an overall secure pivotal connection of the lifting beam to the device for raising and lowering the beam when in use in towin~ a disabled vehicle, this feature being accomplished by positioning of the rollers for engaging the rear face 86 of the lifting device inwardly of the opposing track portions.
Preferably all parts of the towing device are formed 2~ from acceptable grades of plate steel which is welded together ~o form the various components in accordance with acceptable industrial welding techniques. With this arrangement, a minimum of moving parts are provided to provide for extended life of the tow vehicle lift device.
Figure 8 is a perspective view of the wheel lift system as assembled and readied for attachment to the rear gate or truck back of a tow truck;
Figure 9 is a perspective view of the upper portion of the wheel lift system of Figure 8 showing locking of the whee~ lift in the storage position on a tow truck bed;
Figures 10 and 11 show in sequence the lifting of a disabled vehicle; and Figure 12 is an exploded view of components of the wheel lift system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A tow truck generally designated 10, as shown in Figure ~, has a flat bed 12 with rear gate or truck back 14. Two towing systems are provided on the tow truck 10.
The first tow system is the standard well known type of tow sling generally designated 16 and the second towing ~z~
system is a whe~l lift system generally designated 18 according to a preferred embodiment of this invention.
The standard type of tow sling 16 comprises a tow bar 18 connected to the first end portions 20 and 22 of the belted sling 24. The two reinforced rubber belts 26 and 28 extend from the tow bar 19 upwardly and are connected to a sling lift member 30 at their second ends 32 and 3~. The lift bar 30 has a clevice 36 to which a hoist chain 38 or hook may be connected to raise and lower the tow sling. The tow bar 18 is pivotally connected to the gate 14 of the tow truck by a tow sling yoke 40. The yoke 40 comprises two arms 42 and 44. The first ends 46 and 48 of the respective arms are pivotally connected at 50 and 52 to the rear gate by appropriate hinge structures 54 and 56. The second ends 58 and 60 of the arms are pivotally connected to a hinge bracket 62 which, in turn, is secured to the tow bar 18. The yoke 40 is shown in its stowed position. Although not shown, an appropriate loc~ing device may be provided to lock the yoke in its substantially vertical stowed position.
According to this invention, the wheel lift system 18 is arranged to permit storage and removal of the lift system to and from the tow truck flat bed 12 without having to remove the tow slin~. This invention, therefore, enables the use of two separate towing systems which are mutually compatible, in that the tow sling is useful in a variety of situations including disabled vehicles which are severely damaged, whereas the wheel lift system can be used on vehicles which are disabled or have at least one set of wheels which permits towing of the vehicle by the wheels.
With reference to Figure 12, ~he details of the wheel lift are shown. The wheel lift comprises a lift beam 66 which, according to a preferred embodiment of 3S this inven~ion, consists of telescopic members 68 and 70.
Outer sleeve 6~ includes a collar 72 with a threaded aperture 74 through which a threaded locking bolt 76 is provided. The draw bar portion 70 includes three spaced-apart apertures 78, such that when the draw bar is ..~
z~z~
telescoped into the sleeve 68, the locking bolt 76 may be placed in one of the desired apertures 78 to provide various extented lengths for the lift beam 66. The lift beam may be formed of various grades of steel which have sufficient strength to resist the forces placed on the lift beam during use. The sleeve portion 68 may be formed of welded plate, whereas the draw bar 70 may be of solid steel or welded plate steel in a box structure.
The dimensioning of the draw bar 70 is such to ~e snugly received within the opening 80 of the sleeve 68.
The lift beam 66 is pivotally connected to a beam lifting device 82. The beam lifting device 82, in the form of a downwardly depending arm, comprises a tapered box structure having front and rear surfaces 84 and 86 and opposing side surfaces 88 and 90. The box structure may be formed of welded plates where the tapered construction is provided by tapered sides 88 and 90. To the lower end 92 of the beam lifting device 82 a first end 94 of the lift beam 66 is pivotally connected.
According to this preferred embodiment, two generally triangular-shaped plates 96 and 98 are welded to the side portions 100 and 102 of the sleeve 68. The plates 96 and 98 include aligned apertures 104 and 106 which can be placed into register with apertures 108 and 11~. A bolt 112 and lock nut 114 complete the pivotal connection in the form of a hinge arrangement of the plates 96 and 98 to the lower end 92 of the lifting device 82. The positioning of the apertures 104 and 106 in the plates 96 and 98 is such to ensure that the first end 94 abuts the lower portion of the front face ~4 when the lift beam is in the towing position. Hence, the first end 94 abutting the front face 84 of the lift device acts as a stop or device for limiting the exten~ to which the lift beam 66 may pivot downwardly or swing downwardly relative to the lifting device 82.
The beam lift device 82 is pivotally connected at its upper end 116 to a mounting system which interconnects the lifting device to the rear of a tow truck. Such mounting system is adapted to provide for vertical movement of the lift device 82. According to z~
this preferred embodiment, the mounting device includes a carriage 118 which is engaged with a track 120 for riding upwardly and downwardly within the track system 120 The upper portion 116 of the lifting device 82 is pivotally S connected to opposing plate portions 122 and 124 of the carriage 118. Apertures 126 extending through the side walls 88 and 90 are registered with the apertures 128 and 130 in the opposing plates 122 and 124. A bolt 132 and lock nut 134 are used to pivotally interconnect the upper end li6 of the lifting device to the carriage arms 122 and 124. The carriage arms also include two sets of rollers 136 and 138. The rollers are provided to each side of the carriage and are placed within the opposing track channels 140 and 142. The rollers 136 and 138 are secured to axles which in turn are mounted in greased bushings secured to plates 122 and 124. It is appreciated that all types of mounting for the rollers are acceptable, howQver, the bushings provide the most support.
The track channels 140 and 142 are dimensioned to receive the rollers sets 136 and 138 in a manner which captures the rollers and minimizes rocking of the carriage as it rides upwardly and downwardly within the track. At the base of the mounting system 119, are two spaced-apart rollers 144 and 146. These rollers are mounted on an axle 149 which is mounted in greased bushings connected to opposing side walls 150 o the opposing track portions of the track system 120 and to the central portion of the rear plate 148 (not shown).
Rollers 144 and 146 engage the rear face 86 of the lifting device to tilt the lifting device as it is raised over the rollers 144 and 146, the purpose of which is to be explained with respect to Figur~s 10 and 11. The U-shaped tracks 140 and 142 are secured to a rear plate 148 which, in turn, is bolted or welded to the gate of the tow truck. If bolted, apertures 151 may be used. It is appreciated that on either bolting and/or welding the plate 140 to the tow truck gate, sufficient bolts and welds must be used to ensure a permanent secure ~2~6 g connection to withstand the loads placed on the wheel lifting device.
Secured to U-shaped track outer face 152 is a spring loaded locking bolt 154 which is used to lock the carriage in the uppermost load carrying position by engaging aperture 156 in plate 124 of the carriage 118.
Secondly, the locking bolt 154, upon engaging aperture 158 in plate 98 of the lift beam, with the lift beam in stored position on the bed of the truck, locks the lifting beam in the storage position so that it cannot swing out while travelling.
To complete the wheel lift system, the wheel lift devices for engaging the wheels and lifting same are pivotally connected to end 160 of the draw bar 70. A
swivel 162 comprising a hollow rectangular sleeve has secured thereto opposing plates 15~ and 166. The plates include opposing apertures 168 and 170 which are in register with aperture 172 extending through the end 160 of the draw bar 70. A bolt 174 with a nut 176 having a "Nylon" lock is used to complete the pivotal interconnection of the sleeve 162 to the draw bar. Each end of the sleeve includes a rectangular-shaped opening 178 to receive a corresponding rectangular-shaped bar 180 of each wheel lift device 182 which is shown and described in more detail with respect to Figure 8. The bar 180 of each wheel lift device may be inserted through the opening 178 to within the hollow sleeve 162 in the direction of arrow 184. When the wheel lift device is engaged with a vehicle wheel and the beam is lifted, the frictional engagement of the rod 180 within the sleeve 162 resists any sliding movement between the rod 180 and the sleeve 162 and, due to their mating interengagement, resists rotation relative to the lift beam to provide an upward lifting force on the vehicle wheels.
As shown in more detail in Figure 8 with respect to each wheel lifting device 182, it comprises spaced-apart arms 186 and 188. The arms are interconnection at their front portion by a continuation of the rod 180. Secured to the rear face of rod 180 is a wedged-shape plate 190 ~2~Z~;~6 ._. 10 to support a larger circumferential portion of the disabled vehicle wheel 192. Depending upon the size of the wheel, a rod 194 is dropped into respective opposing slots 196 and 198 of the arms 186 and 188 to capture an underside portion of the wheel, such that when the lift is raised, the wheel does not drop between the rod 194 and the wedge l9n to ensure lifting of the vehicle. As is appreciated by those skilled in the art, with this type of wheel lift, it is desirable to place the rod 194 in notches 196 and 198 closest to the wheel.
It is appreciated that the wheel lift system, as assembled in Figure 8, may be sold as a unit which can be attached to the gate of a used tow truck by the truck service operator. Although the unit can be assembled on a new tow truck as original equipment optionally in combination with some other types of tow devices, such as a tow sling. In mounting the plate 148 of the mounting device 119 to the tow truck gate, when the tow truck is already provided with another form of towing device, the rear gate or truck back of the truck, if not adequately supported, should include additional supports and struts to ensure that flexing in the gate is minimized when the wheel lift device is secured to the truck gate.
With the wheel lift system 18 properly secured to the truck gate 14 as shown in Figure Z, the lift beam 66 may be removed by the articulated movement of the lifting device 82 relative to the lifting beam 66. The lifting beam includes two eyes 200 and 202. The tow truck hook 204, as it engages eye 200 as shown in Figure 1, ~lay be used to raise the wheel lift beam 66 onto the tow truck bed 12 in the direction of arrow 206. Due to the articulated folding movement of the wheel lift system, the swivel 162 is permitted to pass beneath the bracket 62 o~ the yoke 40 of the tow sling. The geometry is such that with the carriage 118 in its lowermost position in tracX 120, the extremity of the lifting beam fits and slides smoothly beneath the yoke 40. Hence, the provision of the removable wheel lift devices 182 to leave thereby only the beam which moves through the opening of the yoke 40. In this manner, the invention provides for two vehicle lift systems on a tow truck body to permit lifting of practically all types of disabled road vehicles exclusive of the heavy tandem truck and S other comparable types of large industrial vehicles.
Once the lifting beam has been placed in the storage position on the tow truck bed, as already noted, it is important to ensure that the beam is secured in place so that during transport, it cannot shake loose and fall rearwardly of the tow truck. This may be accomplished by cables or use of the hooX 204 in drawing the lifting device 82 snugly against the rear of the tow truck vehicle. More conveniently, as shown in Figure 9, the releasable lock 15~ has a r~tractable bolt portion 206 for placement in the aperture 158 in plate 98. With the retractable bolt 206 positioned in the aperture 158, the lifting device 82 is held against the gate 14 of the tow truck. When it is desired to remove the liftiny beam from the tow truck bed, the retractable bolt 206 is withdrawn by use of handle 208. The handle 208 can be withdrawn and rotated to position the lug 210 against the exterior face 212 of the sleeve 214 and thereby hold the bolt 206 retracted clear of the aperture 158. Then by use of the tow truck hook 204 placed in eye 202 of the lifting beam, it may be withdrawn from the tow truck bed.
The sequence in removal of the lifting beam from the tow truck bed and the reverse Gf that sequence for placing it on the two truck bed is schematically shown in Figures 3 through 6. The tow truck 10 is equipped with a boom 216 which may be raised and lowered by way of h~draulic ram 218. It is appreciated that the boom may, however, be in the fixed position as held by a cable or the like. A power winch 220 is provided on the structure for the boom 216 to either pay out or reel in cable 222 to which the lifting hook 204 is secured. For purposes of demonstrating the sequence and use of the lifting beam, the second tow structure in the form of a sling has not been shown. To remove the lifting beam 66 from the tow truck bed, the hook 204 may be connected to either of eyes 200 or 202, depending upon the weight distribution in the beam. As shown in Figure 3, the hook 204 is connected to the eye 200 by pulling the lifting beam 66 rearwardly. Either manually or by slightly raising the hook 204, the lifting device may be swung rearwardly to the position shown in Fi~ure 4, The weight of the lifting device 82 in combination with the weight of the beam 66 will now cause the lifting beam to slide rearwardly as it folds against the lifting de~ice 82 until it assumes a position as shown in Figure 5. During this continued rearward movement of the lifting beam 66, its outermost end defined by the swivel connection 162 does not rise above the level indicated by arrow 224, which is the height of the tow bar bracket 62 of the tow sling 16.
During the unfolding action of the lifting device, the carriage 118 remains in its lowermost position in the track 120, such that when the lifting beam 66 is lowered to the ground as shown in Figure 6, the system is ready for lifting a disabled vehicle. The lowering of the beam 6~ to the ground may be either done manually or by repositoning the hook 204 in eye 202 and slowly paying out the cable 222 until the lifting beam 66 is proximate the ground level 226. At this time, the wheel engaging devices 182 are removed from the truck bed and their rectangular-shaped bar portions 180 inserted in the open ended sleeves 162 in preparation for positioning beneath a vehicle ~2~. It is appreciated the reverse of this movement retains the lifting beam 66 to its stowed position on the bed 14 of the tow truck.
The bars 18~ and 188 of the wheel engaging device 182 are sufficiently spaced apart so as to pass by each side of the disabled vehicle tire 230. The wheel engaging bax 194 is then positioned in each wheel engaging device so as to capture the tire between the bar 194 and the wedge 190. Straps or the like may be used to hold the wheels on the devices 182.
~ s shown in more detail in Figure 10, the disabled vehicle 228 is positioned in the wheel engaging devices 182 with the draw bar 70 secured in the outer sleeve 68 of the lifting beam 66 by the locking bolt 76. The sleeve 162 is secured at a slight angle relative to plates 164 and 166 of Figure 12 to locate the devices 182 at ground level with -the lifting arm 66 angled downwardly. The end portion 94 of the sleeve 68 abuts the front face 84 of the lifting device 82. Due to the pivotal connection of the plates 96 and 98 to the sides 88 and 90, the beam will not pivot any further downwardly relative to the lifting device 82. Hence, the first end 94 of the lifting beam 66 acts as a stop to limit the extent to which the lifting beam can swing downwardly relative to the lifting device 82. The carriage 118 is in its lowermost position as determined by paying out the cable 222 for the hook 204 as it engages the opening 232 in the front face 84 of the lifting device. The shape of the aperture 232 in the front face of the lifting device is shown in more detail in Figure 12. The rear face 86 of the lifting device 82 is in contact with the rollers 144, 146 which are secured to the lowermost portion of the track 120. By tapering the side faces 88 and 90 of the lifting device 82, the front face 84 of the lifting device is swung outwardly relative to the track 120 by its pi~otal connection at 126 to the carriage 118.
Upon raising of the tow hook 204 by reeling in the cable 222, the rear face 86, as it rides upwardly over the rollers 144, 146, pivots the lifting device 82 outwardly away from the track 120. This swings the lifting beam 66 upwardly relative to the track 120 to ensure that the lifting ~eam 66 does not interfere with the underside 234 of the disabled vehicle 228. In addition the angled relationship of the sleeve 162 to the plates 16~ and 166 prevents the devices 182 from sloping downwardly as the arm 66 is lifted. Any slack in the interconnections of arm 70 in sleeve 68 and at other joints in the lifting device are compensated for by the angle relationship of the sleeve 162 in the plates 164 and 166. Hence when a car is raised as shown in Figure 11, the devices 182 extend outwardly from the lifting arm Z~
in essentially the same plane. The engagement of the rollers 136 and 138 with the interface 236 of each track channel 1~0 and 142 captures the carriage 118 in its vertical movement from its lowermost to uppermost position. When the carriage 118 is in its uppermost position, the loc]c bolt 154 may be inserted in aperture 156 of the carriage, as shown in more detail in Figure 12, to lock the carriage in the uppermost position to provide an additional safety factor to ensure that the vehicle is not dropped during the towing process, should for example, the cable 222 break and release the hook 204.
The roller system for the carriage is of sturdy construction and preferably includes provisions for frequent greasing of the rollers. In addition, the rollers 144 and 146 are provided with greased fittings.
By forming the track channels 140 and 142 from sufficiently thick, high grade, steel plate, the forces of the set of rollers 136 and 138 are distributed over the innerfaces 236 of the tracks to prevent bending of the track interfaces. A solid construction is provided in pivoting the lifting device 82 to the carriage where the lifting device is supported on its rear face by the rollers 144 and 146. As explained with respect to Figure 11, such roller engagement not only provides for support of the lifting device in limiting the extent to which the lifting device pivots towards the track, but also provides for a kick out or pivoting of the lifting beam relative to the track to ensure that it clears the lower portion of the disabled vehicle when lifted. The pivoted connection of the lifting beam 66 to the lifting device 82, which includes means for limiting the extent of downward swinging of the beam, provides a folding action of the beam towards the lifting device to permit positioning of the beam onto the tow truck bed in ~n efficient compact manner, while taking up little space and preferably when used in combination with a tow sling, the free end of the lifting beam with the wheel engaging 2~
device removed slides beneath the inverted V-shaped yoke of the tow sling device~
As shown in Figures 10 and 11, the side portions 88 and 90 of Lhe lifting device 82 always remain within the opposing edges 141 and 143 as shown in Figure 12 due to the positioning of the rollers 144 and 146. This confinement of the side edges of the lifting device within the track minimizes the chance of sway of the lower portion of the lifting device relative to its pivotal connection to the carriage 118. To lend additional support in confining the sides of the lifting device, lugs 238 and ~40 are provided at the lower ends track edges 141 and 143. These lugs in combination with the opposing edges 141 and 143 of the track minimize the lateral movement of the lifting device during vertical travel of the carriage. This reduces torsion on the carriage device during the carrying of heavy loads and thereby providing an overall secure pivotal connection of the lifting beam to the device for raising and lowering the beam when in use in towin~ a disabled vehicle, this feature being accomplished by positioning of the rollers for engaging the rear face 86 of the lifting device inwardly of the opposing track portions.
Preferably all parts of the towing device are formed 2~ from acceptable grades of plate steel which is welded together ~o form the various components in accordance with acceptable industrial welding techniques. With this arrangement, a minimum of moving parts are provided to provide for extended life of the tow vehicle lift device.
3~ The rollers at the base of the track, which engage the rear face of the lifting device, are adequately supported to withstand the forces exerted on this point of the lifting device during lifting and towing of vehicles.
Although preferred embodiments of ~he invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
Although preferred embodiments of ~he invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A vehicle wheel lift towing apparatus for mounting onto a rear portion of a tow truck, said apparatus comprising a rigid lift beam for positioning beneath a disabled vehicle, wheel lift means provided to each side of and interconnected to said beam for engaging and lifting a set of disabled vehicle wheels, beam lift means adapted for vertical lifting movement when in use on a tow truck, means for mounting said beam lift means to a rear portion of a tow truck, said mounting means being adapted to provide for vertical travel of said lift means from a lower vehicle wheel lifting position to an upper vehicle towing position, said lift means including a downwardly depending arm, a first end of said depending arm being pivotally connected to said mounting means, a first end of said lift beam being pivotally connected to a lower portion of said depending arm, means for limiting downward swinging movement of said lift beam relative to said lift means to define a wheel lift position for said lift beam, said pivotal connection of said lift beam to said lift means permitting hinged movement of said lift beam towards said lift means when said lift means is swung out onto a tow truck for storage of said lift beam.
2. An apparatus of claim 1, wherein means releasably interconnects said wheel lift means to each side of said lift beam, said wheel lift means being removable from said lift beam prior to swinging said beam to a storage position on a tow truck.
3. An apparatus of claim 1, wherein said mounting means comprises a carriage and a track, said carriage being engaged with said track for vertical movement of said carriage, said first end of said lift means being pivotally mounted on said carriage.
4. An apparatus of claim 3, wherein limit means is provided at a lower portion of said track for engaging said lift means to limit inward swinging movement of said lift means relative to said track.
5. An apparatus of claim 4, wherein said lift means is elongate and includes a cam extending in a length direction of said lift means, said cam engaging said limit means during vertical travel in lifting a disabled vehicle, said cam being shaped to pivot said lift means outwardly relative to said track to tilt upwardly thereby said lift beam.
6. An apparatus of claim 3, wherein said carriage comprises a rigid body to which said lift means is pivoted, two sets of rollers mounted on said body, said rollers being oriented for travel along said track, said track comprising opposing spaced-apart U-shaped channels to receive said rollers, said rollers being captured in said channels to minimize rocking motion of said carriage as it moves vertically in said channels.
7. An apparatus of claim 6, wherein said lift means comprises a body portion with front and rear faces and opposing side faces, track roller means being mounted in a lower portion of said track for engaging said rear face of said lift means body portion, said track roller means limiting the extent to which said lift means pivots inwardly relative to said track.
8. An apparatus of claim 7, wherein spaced-apart guides are secured to said opposing channels, said guides precluding sway of said lift means by engaging either of said side faces of said lift means body.
9. An apparatus of claim 7, wherein said front face of said lift means body includes hook means beneath said pivotal connection to said carriage and to which a tow truck lift hook may be engaged for power lifting of said lift means to lift a disabled vehicle.
10. An apparatus of claim 7, wherein said lift beam comprises top, bottom and opposing side faces, a plate secured to each side face proximate said first end of said lift beam, each of said plates being pivotally connected to a corresponding side face of said lift means body, said first end of said beam abutting said front face of said lift means body to limit thereby downward swinging movement of said lift beam and define said wheel lift position for said lift beam.
11. An apparatus of claim 2, wherein said interconnection means for said wheel lift means is pivotally connected to a second end of said lift beam.
12. An apparatus of claim 11, wherein said wheel lift means comprises a rectangular shaped bar secured to means for engaging a vehicle wheel, said interconnection means comprising a hollow rectangular sleeve of a size to snugly receive said rectangular bar thereby frictionally locking said wheel lift means to said interconnection means when a disabled vehicle is lifted.
13. An apparatus of claim 6, 10 or 12, wherein said lift beam comprises telescopic members, means for releasably securing said telescopic members in various adjusted extended relative positions.
14. An apparatus of claim 6, 10 or 12, wherein said lift beam includes near its second end hook means to which a tow truck lift hook may be engaged for power lifting of said lift beam onto a tow truck for storage.
15. An apparatus of claim 2, wherein said lift beam swings towards said lift means to provide a folding action of said towing apparatus when said lift beam is raised for storage on a tow truck, said folding action of said towing apparatus permitting swinging of said lift beam beneath a tow sling yoke or the like of other towing devices previously mounted on a tow truck.
16. A tow truck provided with two types of disabled vehicle lift systems, a first lift system comprising a tow sling system and a second lift system comprising a wheel lift system, said tow sling system comprising a tow bar connected to one end of a belt sling, a yoke pivotally interconnecting said tow bar to a rear gate or truck back portion of said tow truck, a boom winch with hook is provided and hooked to the other end of said belt sling, said yoke comprising two arms, a first end of each said arm being pivotally connected at spaced-apart locations to said rear gate or truck, a second end of each said arm being pivotally connected to said tow bar, said yoke being in a raised position during storage with said tow bar beneath said boom, said wheel lift system comprising a rigid lift beam for positioning beneath a disable vehicle, wheel lift means provided to each side of and interconnected to said beam for engaging and lifting a set of disabled vehicle wheels, beam lift means adapted for vertical lifting movement, means for mounting said beam lift means to said rear gate or truck back at a location between said first ends of said yoke arms, said mounting means being adapted to provide for vertical travel of said lift means from a lower vehicle lifting position to an upper vehicle towing position, said lift means including a downwardly depending arm, a first end of said depending arm being pivotally connected to said mounting means, a first end of said lift beam being pivotally connected to a lower portion of said depending arm, means for limiting downward swinging movement of said lift beam relative to said lift means to define a wheel lift position for said lift beam, said pivotal connection of said lift beam to said lift means permitting hinged movement of said beam towards said lift means and said pivotal connection of said lift means to said mounting means permitting folding of said lift beam towards said lift means, such folding of said wheel lift system permitting swinging of said lift beam through said yoke arms and beneath said tow bar for positioning on said tow truck bed, said wheel lift means being releasable from said lift beam for storage and facilitating passage of said lift beam between said yoke arms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000491032A CA1212926A (en) | 1985-09-18 | 1985-09-18 | Wheel lift towing apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000491032A CA1212926A (en) | 1985-09-18 | 1985-09-18 | Wheel lift towing apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1212926A true CA1212926A (en) | 1986-10-21 |
Family
ID=4131424
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000491032A Expired CA1212926A (en) | 1985-09-18 | 1985-09-18 | Wheel lift towing apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1212926A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6357645B1 (en) | 1999-08-13 | 2002-03-19 | David Keefe | Release pull bar holster |
| EP2269868A1 (en) * | 2009-06-30 | 2011-01-05 | Omars S.p.A. | Wheel-lift assembly for wreckers |
-
1985
- 1985-09-18 CA CA000491032A patent/CA1212926A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6357645B1 (en) | 1999-08-13 | 2002-03-19 | David Keefe | Release pull bar holster |
| EP2269868A1 (en) * | 2009-06-30 | 2011-01-05 | Omars S.p.A. | Wheel-lift assembly for wreckers |
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