|Publication number||US3907254 A|
|Publication date||Sep 23, 1975|
|Filing date||Mar 22, 1973|
|Priority date||Mar 22, 1973|
|Publication number||US 3907254 A, US 3907254A, US-A-3907254, US3907254 A, US3907254A|
|Inventors||Richards Thomas J|
|Original Assignee||Richards Thomas J|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (6), Classifications (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 11 1 Richards Sept. 23, 1975  LIFTING APPARATUS 1.489.355 4/1924 Knowllon 254/120 7 07 9 R x  Inventor: Thomas J. Richards, 3070 King Rd., 26 5 4H 73 ymua 254/78 Saginaw, Mi h, 4860! FOREIGN PATENTS OR APPLICATIONS 356,495 9/l92l Germany 254/21  Mai 1973 308,l69 10/1917 Germany 254/21 [2|] Appl. N(J.Z 343,638
Primary ExaminerAl Lawrence Smith Assistant Examiner-Robert C. Watson Attorney Agent or Firm J0hn J. Swarm  Field of Search 254/l3l, 120. H3, [32.
254/123, 30, 78; 29/267; 74/25, 54, 55, 519  ABSTRACT Apparatus for lifting a load, such as one end of a  R fer n cu d snowmobile or the like, including a swingable lifting UNITED STATES PATENTS lever pivotally mounted on a movable fulcrum for rais- 19 H0 5/l877 Case 254/13 ing a load in a linear path of travel. 4653837 l2/189l Critcher 254/120 14 Claims, 4 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of2 3,907,254
US Patent Sept. 23,1975 Sheet 2 of 2 3,907,254
LIFTING APPARATUS BACKGROUND OF THE INVENTION This invention relates to lifting apparatus and more particularly to apparatus incorporating a swingable lifting lever which lifts a load in a linear path of travel and which can be automatically locked in a load-lifting position.
When the endless drive track or the bogey wheels of a snowmobile are serviced or adjusted, at least the rear end of the snowmobile is lifted. When snowmobiles are stored, they are lifted off the ground to prevent flattening of the bogey wheels and stretching of the track. Snowmobiles are relatively heavy, somewhat cumbersome, difficult to manually lift. and difficult to manually hold in an elevated position for a sustained period of time. Manual lifting of snowmobiles can cause serious back strain and represents a safety hazard because of the possibility of the machine slipping out of the lifters grasp. Accordingly. it is an object of the present invention to provide apparatus for lifting one end of a snowmobile or the like.
It is another object of the present invention to provide apparatus for lifting one end of a snowmobile and holding it in a raised position.
Since a snowmachine is relatively heavy, it is impor tant that apparatus be provided for lifting the snowmobile with a mechanical advantage. A lever can be used to achieve a mechanical advantage, but in the conventional lifting devices incorporating a lever, not all of the force exerted by the lever on the load is resolved vertically but rather it is resolved into horizontal and vertical components. The horizontal components of force does not contribute to the lifting and thus the efficiency of such apparatus is accordingly reduced. If the horizontal force component is substantial, the lifting device will be unstable and may tip over, possibly injuring bystanders. Accordingly, it is another object of the present invention to provide laterally stable lifting apparatus which will lift the load in a substantially linear vertical path of travel.
A further object is to provide lever lifting apparatus of the type described wherein the force exerted by the lever on the load is substantially vertically resolved.
When a load is lifted to a raised position, it is important that the lifting apparatus be automatically locked in the raised position so that the operator need not remove his hands from the force applying handle of the apparatus until after the load is locked in a raised position. Accordingly, it is another object of the present invention to provide lifting apparatus of the type described which incorporates a lock which will automatically lock the lever in a lifted position.
Because of the injury which could result if the lifting lever was inadvertently knocked out of its locked position, it is important that an additional safety lock be provided to insure that the lever will remain in the locked position to positively prevent the load from being inadvertently dropped. Still another object of the present invention is to provide apparatus of the type described including an additional safety lock for positively insuring that the lever remains in the locked position.
Other objects and advantages of the present inven tion will become apparent to those of ordinary skill in the art as the description thereof proceeds.
SUMMARY OF THE INVENTION Apparatus for lifting a load, such as one end of a snowmobile or the like. comprising a frame, an actuating lever, swingably mounted on the frame, coupled to a lifting lever which is movable in such a swinging path of travel that a load supported by the lifting lever is lifted in a substantially linear path of travel.
The present invention may more readily be understood by reference to the accompanying drawings in which:
FIG. 1 is a side elevational view of lifting apparatus constructed according to the present invention;
FIG. 2 is a sectional top plan view taken along the line 2-2 of FIG. 1; and
FIGS. 3 and 4 are side elevational views illustrating the lifting apparatus in sequential lifting positions.
Lifting apparatus, constructed according to the present invention and generally designated 6 is particularly adapted for use in lifting the rear end R of a snowmobile, generally designated S, having a lifting bar 8 at its rear end as usual.
The lifting apparatus comprises a frame, generally designated F, including a base 10 mounting an upstanding support member 12 having a cam plate 14 at its upper end provided with a curvilinear cam surface 14a. Pivotally mounted on the cam plate 14, by a pivot pin 16, is an actuating lever arm, generally designated 18, having a bifurcated section 20 mounted on the pin 16 and a hand gripping portion 22 which can be manually gripped for swinging the lever 18 about the axis a of the pin 16.
A lifting lever, generally designated 21, includes a pair of laterally spaced, longitudinal arm sections 22a (FIG. 2) swingably connected to the actuating lever 18 by a pivot pin 24 for swinging movement therewith about the axis a of pin 16 and for swinging movement relative thereto about the axis 1) of the pin 24. The free ends 22b of the lever arm sections 22a are spanned by a lift pin 26, having a horizontal axis c. The pin 26 supports a link chain 28 mounting an S-shaped lift hook 30 which is adapted to underlie the lift bar 8 at the rear end of the snowmobile S.
A cam follower roller 32, constituting a movable fulcrum for the lifting lever 21, is journaled on a shaft 34 spanning the longitudinal lever arm sections 22a and is peripherally grooved at 36 for receiving the edge 14a of the underlying plate 14. The profile of the cam 14 is such that, as the lever arm 21 is swung by the actuator lever arm 18 from the position illustrated in FIG. I to the position illustrated in FIG. 3, the free end 2211 of the lifting lever 21 moves in a substantially linear, path of travel. in a vertical plane schematically designated p.
When the load support lever arm 21 and the actuating lever arm 18 are in the rearward positions illustrated in FIG. 3, the axes u. h and c of the pins 16, 24, and 26 all lie in the same horizontal plane so that any component of force exerted on the lifting lever arm 21 in a horizontal direction I: will not swing the levers 18 and 21 clockwise in the direction of the arrow i. When the lifting lever arm 21 is in the position illustrated in FIG. 3, the axis oflift pin 26 is slightly rearward of the vertical plane 1 but as the lever arm 21 continues to swing to the position illustrated in FIG. 4, the lift pin 26 is again returned to a position in which the axis 0 lies in the plane p. The snowmobile lifting bar 8 is thus positioned substantially directly over its former position at ground level.
When the lifting lever arm 21 and the actuating lever arm 18 swing downwardly from the positions illustrated in FIG. 3 to the positions illustrated in FIG. 4, stops 37, mounted on the cam plate 14 in the path of the arm 21, interrupt movement thereof. The pin 24 follows an are having a radius r relative to its axis a. When this happens, the pivot pin 24 is in an over-center" position and the weight of the snowmobile S on the free end 25 of the lifting lever arm 21 will tend to swing the lifting lever 21 clockwisely about the stop pins 37 which now comprise an auxiliary fulcrum for the lifting lever 21. The pivot pin 24 will tend to swing about the axis of the pin 37 in an are I which has a smaller radius r relative to the axis a than the radius r. (FIG. 4). The lifting lever arm 21 will thus be locked in the position illustrated in FIG. 4.
To prevent the serious injury which could result if a workman lying beneath the snowmobile S inadvertently kicked the actuating lever arm 18 clockwise in the direction of the arrow i (FIG. 4), a locking pin 38 is inserted in an aperture 40 provided in the cam plate 14. The S-shaped lift hook can. of course, be supported by different links 28a of the chain 28 to accommodate snowmobile lift bars 8 which are at different levels.
THE OPERATION The lifting jack 6 is moved to a position at the rearward end of the snowmobile S and the S-shaped lifting hook 30 is supported by a suitable chain link 28a so that it will be received under the snowmobile supported lifting bar 8 when the lifting lever arm 21 is in the forward position illustrated in chain lines in FIG. 2. The actuating lever arm 18 is then swung rearwardly in a counterclockwise direction. and the lifting lever arm 21 is guided by the cam 14a and the roller 32 in such a path that the end 25 of the lifting lever 21 moves in a linear path of travel. This lifts the rear end of the snow mobile in a linear path of travel without causing it to move rearwardly.
As the lifting lever arm 21 swings from the position shown in FIG. 3 to the position illustrated in FIG. 4. the pin 26, which was moved only slightly rearwardly at the upper end of its path of travel. again moves forwardly to intersect the vertical plane p. As the lifting lever is swung to the position illustrated in FIG. 4, the lifting lever arm 21 is supported by the stops 37. The locking pin 38 is then inserted in the aperture 40 to positively prevent the actuating lever from swinging in a clocl wise direction. To lower the machine. the locking pin 38 is removed and the actuating arm 18 is swung in a clockwise direction. represented by the arrow i.
It is to be understood that the drawings and descrip tive matter are in all cases to be interpreted as merely illustrative of the principles of the invention. rather than as limiting the same in any way. since it is contemplated that various changes may be made in various ele ments to achieve like results without departing from the spirit of the invention or the scope of the appended claims.
What is claimed is:
1. Apparatus for lifting and supporting a load. such as a portion of a snowmobile and the like comprising:
actuating lever means pivotally mounted on said frame for pivotal movement about an axis between generally forward and rearward positions;
load supporting means having one end pivotally coupled to said lever means for swinging movement therewith in an orbital path about said axis between forward and rearward positions and for swinging movement relative thereto, said support means having a free end for supporting said load movable between lowered and raised positions as said one end moves between said forward and rearward positions;
means for guiding the front to rear and swinging movement of a portion of said support means relative to said frame and said lever means as said lever means and said support means swing to guide said free end in a substantially linear, vertical path of travel;
said support means being mounted such that the load exerted on said free end urges the lever means in said forward position in one direction of rotation about said first axis and in said rearward position in an opposite direction of rotation; and
means for interrupting rotation of said lever means in said opposite direction after a predetermined rotation of said lever means in said opposite direction to lock said load supporting means in a stable load supporting position.
2. The apparatus of claim 1 wherein said guiding means comprises cam means on said frame and cooperating cam follower means on said support means for guiding the movement of said support means.
3. The apparatus of claim 2 including means swingably connected to the free end of said support means for underlying a portion of said load to be lifted.
4. The apparatus of claim 3 wherein said lever means is pivotally mounted about a first horizontal axis, said support means is pivotally connected to said lever for swinging movement thereon about a second axis; said means for underlying a portion of said object is swingable about a third axis; said support means being swingable about said second axis between a position in which said second axis overlies a plane intersecting said first and third axes and an over-center locking position in which said second axis underlies said plane.
5. The apparatus of claim 4 including stop means underlying said plane to interrupt swinging movement of said support means downwardly away from said plane.
6. The apparatus of claim 5 including lock means for positively insuring that said support means remains in said over-center position to prevent said lever means from being inadvertently swung to a position in which said lever means is overlying said plane.
7. The apparatus of claim 4 wherein said second axis is positioned rearward of said first axis as said support means swings between said overlying and underlying positions.
8. The apparatus of claim 4 wherein said guiding means guides said underlying support means for movement slightly rearwardly and then return as said support means is in said raised position and swings between said positions in which said second axis overlies and underlies said plane.
9. Apparatus for lifting a load such as one end of a snowmobile and the like comprising:
an upstanding support frame;
a lever pivotally mounted on said frame for swinging movement about a first horizontal axis; a load lifting arm pivotally coupled to said lever via a pivot pin; and
movable fulcrum means mounting said arm interjacent its ends on said frame for movement therewith relative to said pivot pin;
said load lifting arm having a free end for supporting said load for swinging movement about a third axis and an end opposite said free end pivotally mounted via said pivot pin on said lever for swinging move ment therewith and for swinging movement relative thereto about a second horizontal axis in an arcuate path of travel between a position in which said second axis lies on one side of a plane intersecting said first axis and said fulcrum means and an overcenter position in which said second axis lies on the opposite side of said plane to lock said load lifting arm in said overcenter position.
10. The apparatus of claim 9 wherein said lever is swingable between forward and rear positions to move said opposite end rearwardly to a position in which said third axis is rearward of said first axis as said lifting arm swings between said overlying and underlying positions.
1 l. The apparatus as set forth in claim 9 wherein said one end of said lever moves in a substantially linear, vertical path of travel as said lever swings about said fulcrum means.
12. Apparatus for lifting a load such as one end of a snowmobile and the like comprising:
an upstanding support frame;
a lever having a forward end for supporting a load to be lifted: and
means mounting said lever on said frame for swinging movement such that one end moves in a vertical, linear path between a lower position and a raised position and then transversely to said vertical path as said one end reaches said raised position;
said mounting means including load bearing fulcrum means vertically supporting said lever between its ends on said frame for movement thereon in a toand-fro curvilinear path of travel transverse to said vertical path said one end of said lever extending beyond said fulcrum means.
13. The apparatus as set forth in claim 12 including link means mounted on said frame for swinging movement about an axis; the other end of said lever being pivotally coupled to said link means for concurrent movement about said axis.
14. The apparatus as set forth in claim 13 wherein said link means includes operating means coupled between said frame and the other end of said lever for swinging said lever about said fulcrum means and concurrently moving said fulcrum means and at least a portion of said lever in said arcuate path relative to said frame to raise said one end of said lever in said linear path.
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