US2467657A

US2467657A - Scissors jack

Info

Publication number: US2467657A
Application number: US668430A
Authority: US
Inventors: William P Brown
Original assignee: FRED LAKE
Current assignee: FRED LAKE
Priority date: 1946-05-09
Filing date: 1946-05-09
Publication date: 1949-04-19
Anticipated expiration: 1966-04-19

Description

April 19, 1949. w. P. BROWN 2,467,657

SCISSORS JACK Filed May 9, 1946 I 2 Shets-Sheet 1 INVENTOR- W/kw ffimwy gar/am YZ@%M April 19, 1949.

w. P. BROWN SCISSORS JACK Filed May 9, 1946 2 Sheets-Sheet 2 I IN VEN TOR.

3W WM Patented Apr. 19, 1949 SCISSORS JACK William P. Brown, Detroit, Mich., assignor of forty-nine per cent to Fred Lake, Marion, Ohio Application May 9, 1946, Serial No. 668,430

14 Claims.

This invention relates to jacks for raising and lowering objects, such as vehicles, and in particular to so-called scissors jacks having toggle linkage mechanisms therein.

One object of this invention is to provide a scissors jack wherein the crossing links are synchronized and operatively interconnected by crank mechanisms extending from certain of the pivot pins thereof to the cross blocks of the operating screw.

Another object is to provide a scissors jack as set forth in the preceding object whereby the crank mechanism enables the jack to exert a powerful mechanical advantage which assists in raising and lowering abnormally heavy loads with increased facility, particularly when the jack is in its lowermost position.

Another object is to provide a scissors jack as set forth in the preceding objects, wherein the operating screw swings during the raising operation from an initial position with the end of the screw nearest the operator tilted downward to a final position with the screw tilted upward, thereby enabling the operator to insert the operating handle in a very limited space and operate it conveniently during the initial raising action of the jack, when the load is nearest the ground or floor level, and the available space is greatly restricted.

Another object is to provide a scissors jack as set forth in the preceding objects, wherein each crank mechanism consists of a pair of spaced crank arms fixedly mounted on and secured to the pivot pin, and a link pivotally connecting the end of each crank with one of the cross blocks through which the operating screw shaft passes, thereby providing a powerful yet simple connection therebetween.

Another object is to provide a scissors jack as set forth in the object immediately preceding, wherein the crank arms and crank links are disposed inwardly of the crossing links where they are out of the way and closely spaced so as to provide a stronger construction.

Other objects and advantages will become apparent during the course of the following description of the accompanying drawings, wherein:

Figure 1 is a side elevation of the improved scissors jack of this invention, according to a preferred embodiment thereof, showing the jack in its raised position;

Figure 2 is a right-hand elevation of the scissors jack shown in Figure 1;

Figure 3 is an approximately horizontal section through the plane of the operating screw shaft taken along the line 33 in Figure 1; 7

Figure 4 is a horizontal section taken along the line 44 in Figure 1;

Figure 5 is an inclined section through the lower crossing link and crank mechanism taken along the line 55 in Figure 1;

Figure 6 is a detailed fragmentary vertical section showing one form of connection of a crank arm to its pivot pin;

Figure 7 is a perspective view of the connection bushing shown in Figure 6; and

Figure 8 is a view similar to Figure 6 but showing a connection employing a pivot pin of D- shaped cross-section.

Referring to the drawings in detail, Figure 1 shows a preferred embodiment of the scissors jack of this invention as mounted upon a base ID of plate-like form having upturned ends II to facilitate moving the jack along the ground or floor. Rising from the base H] are spaced pairs of lugs l2 and I3 upon which are pivotally mounted two pairs of lower crossing links l4 and I5 respectively. The crossing links I5 are mounted upon pivot pins l6 (Figures 1 and 4) of circular cross-section with enlarged outer ends, the pins l6 passing through aligned bores I1 and I8 in the crossing links l5 and lugs l3 respectively.

The lower ends of the crossing links M, on the other hand, are provided with square bores IQ for receiving the opposite ends of a pivot pin 20 of square cross-section (Figures 1 and 4), said ends being likewise enlarged to secure the parts together. The lugs l2 are provided with enlarged circular borers 2i for receiving the peripheries of cylindrical bushings 22 (Figures 6 and 7) which thereby serve as bearing bushings. The bushings 22 have bores 23 of square cross-section corresponding to and receiving the pivot pin 20 of square cross-section.

Likewise mounted on the square-section pivot pin 20 inwardly of the lugs I2 is a pair of crank arms 24 having square bores 25 therein corresponding to and receiving the square-section pivot pin 20. In this manner, a rigid and positive mechanical connection is provided between the crank arms 24 and lower crossing links I4. A spacing sleeve 26 is mounted upon the pivot pin 20 (Figures 4 and 5) between the crank arms 24 and serves to maintain them securely adjacent the inner surfaces of the lugs l2.

The crank arms 24 are relatively short in comparison with the crossing links M and at their outer ends (Figure 4) are provided with bores 2! for receiving pivot pins 28 which pass through aligned bores 29 in connecting links 39 and have their opposite ends enlarged to secure the crank arms 24 and links 30 together. The upper ends of the connecting links 30 (Figures 1 and 3) are bored as at 3| to receive the oppositely extending projections 32 of the forward cross block 33. The projections 32 are in the form of pins integral with the block 93 and also pivotally receive the upper ends of the lower crossing links 15 and the lower ends of upper crossing links 34, the links l5 and 34 having

bores

35 and 35 respectively for this purpose (Figure 3). The outer ends of the projections 32 are also enlarged to retain the parts in assembly.

The forward cross block 33 is provided with a transverse bore 31 for rotatably receiving the smooth portion 38 of an operating screw shaft 39, the latter having a collar 40 and a retaining pin 4| passing through a transverse hole 42 therein. The collar 49 cooperates with an antifriction thrust bearing 43 disposed on the opposite side of the cross block 33 and consisting of a cup-shaped outer race 44 (Figure 1) and an annularly grooved inner race 45 for receiving ball bearings 46. The thrust bearing 43 is held in position against the cross block 33 by a sleeve 4! pinned as at 48 (Figure 1) to the forward end of the screw shaft 39. The latter terminates within the bore 49 of the sleeve 4! to provide a socket through which a transverse coupling pin 50 extends, passing through holes 5| in the sleeve 41. The coupling pin 50 has its ends projecting transversely from the sleeve 41 and cooperates with the forward end of the bore 49 to receive the end of a conventional operating handle (not shown) having means thereon, such as bayonet slots, for releasably engaging the coupling pin 50. Such operat ing handles are well-known and their details form no part of the present invention.

The screw shaft 39 is provided with a screwthreaded portion 52 (Figure 3) which passes through a correspondingly threaded bore 54 in a rearward cross block 55. The latter resembles the forward cross block 33 in having similar projections 56 extending from the opposite sides thereof and serving as pivot members for pivotally receiving the upper ends of the lower crossing links 54, the lower ends of upper crossing links 5'! and the lower ends of upper connecting links 58 similar to the lower connecting links 39 and similarly pivoted to the free ends of upper crank arms 59, likewise similar to the lower crank anms 24. The links I4, 51 and 58 (Figure 3) are provided with bores 60, GI and 62 respectively for this purpose. The projections 56 are also enlarged at their ends to hold the links [4, 5'! and 58 in assembly.

The pivotal connection between the connecting links 58 and crank arms 59 is made by pivot pins 63 identical in construction to the pivot pins 28 (Figure 4) and their opposite ends are fixedly secured to a square-section pivot pin 64 (Figure 1) passing through squared holes therein. The upper ends of the upper crossing shaft 34 are likewise provided with squared holes engaging the square-section pivot pin 64 which passes through bushings 66 identical with the bushings 22 (Figures 6 and '7) and having the same square holes 23 therethrough. The bushings 66 are mounted in circular holes 61 passing through spaced lugs 58 extending downwardly from and integral with a load rest or saddle 59 of platelike form and having upturned ends 10 for preventing the load, such as a vehicle axle, from accidentally slipping off. The construction of the upper pivot pin 64 and its associated parts is identical with that of the lower pivot pin 20 and its associated parts (Figure 4), hence requires no duplication of description. The load rest 59 is also provided with forward lugs ll similar to the lugs l3 on the base It] and having similar bores 72 (Figure 2) for receiving the pivot pin 13 of circular cross-section. The pivot pin 13 passes through bores '14 in the upper ends of the upper crossing links 5'! and the outer ends thereof are enlarged to hold these parts in assembly.

The modification shown in Figure 8 provides a simplified yet positive connection between the crank arms 24 and 59 and the crossing links [4 and 34 respectively. For this purpose, the pivot in 29 of square cros:-section is replaced by a pivot pin 15 of D-shaped cross-section having a fiat portion l6 engaging the corresponding fiat portion 17 of a D-shaped hole 18 in the ends of the crank arms 24 or 59 and the crossing links M or 34 to which they are positively connected. The crossing links 94 or 34 are provided with similar holes of D-shaped cross-section for receiving the ends of the pivot pin 35 and the latter passes through aligned circular bores T9 in the lu s [2 or 63 respectively. The modification of Figure 8 eliminates the necessity for the bushings 22 and 59 (Figures 6 and 7) since the curved portion of the pivot pin 75 has a bearing engagement with the bores '19, whereas the flat portions 16 and T! provide a positive mechanical engagement which may be additionally strengthened, if desired, by tack welding thereat.

In this manner, the lower and upper links l4, i5, 34 and 51 provide a toggle linkage primarily actuated by the screw shaft 39 and assisted in its actuation by the crank mechanism including the crank arms 24 and 59 and the connecting links or

pitmans

30 and 58.

In operation, let it be assumed that the scissors jack is in its raised position shown in Figure 1, with a load 8! indicated by the dotted lines supported on the load rest or saddle 59. Such a load, for example, may consist of a vehicle with a front axle 8|. To lower the load 8|, the operator affixes a conventional handle to the sleeve 41 by means of the coupling pin 50 and rotates the screw shaft 39 in the proper direction. This action causes the cross block 55 to move away from the cross block 33, permitting the crossing links l4, I5, 34 and 51 to swing into more nearly horizontal positions. The crank arms 24 and 59, by their positive connection with the crossing links l4 and 34 through the connecting

links

30 and 58, synchronize the motion of these links and prevent the load rest or saddle 69 from moving laterally a sufficient distance to otherwise collapse the jack. The operator continues the turning of the screw shaft 39 until the load rest 69 approaches the base I 0, its minimum permissible distance.

To raise the load 8|, the operator reverses the foregoing procedure by rotating the handle and screw shaft 39 in the opposite direction, causing the cross block 55 to be pulled toward the cross block 33, and swinging the links l4, I5, 34 and 5'! into more nearly vertical position. At the same time, a powerful lifting and synchronizing force is transmitted through the

links

30 and 58, the crank arms 24 and 59 and the pivot pins 20 and 65 to the respective crossing links [4 and 34 to synchronize the swinging thereof and provide additional points of application of the lifting force.

While I have shown and described my invention in detail, it is to be understood that the same is to be limited only by the appended claims, for many changes may be made without departing from the spirit and scope of my invention.

What I claim is:

1. A scissors jack comprising a base member, a top member, a toggle linkage interconnecting said members, an operating device operatively interconnecting the intermediate portions of said linkage and arranged to move said portions laterally toward one another whereby to lift said top member, and a crank mechanism additionally connecting said operating device with said toggle linkage, said crank mechanism being responsive to the motion of said operating device to synchronize the upward motion of said top member with the lateral motion of said intermediate linkage portions,

2. A scissors jack comprising a base member, a top member, a toggle linkage interconnecting said members, an operating device operatively interconnecting the intermediate portions of said linkage and arranged to move said portions laterally toward one another whereby to lift said top member, and a crank mechanism additionally connecting said operating device with said toggle linkage adjacent one of said members, said crank mechanism being responsive to the motion of said operating device to synchronize the upward motion of said top member with the lateral motion of said intermediate linkage portions.

3. A scissors jack comprising a base member, a top member, a toggle linkage interconnecting said members, an operating device operatively interconnecting the intermediate portions of said linkage and arranged to move said portions laterally toward one another whereby to lift said top member, and a crank mechanism additionally connecting said operating device with said toggle linkage, said crank mechanism comprising a shaft operatively connected to said linkage adjacent one of said members, a crank arm connected to said shaft, and a pitman connecting said crank arm with said operating device.

4. A scissors jack comprising a base member, a top member, a pair of laterally spaced across elements disposed between said members, upper and lower pairs of toggle links having their inner ends pivoted to said cross elements and their outer ends pivoted to said members, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a crank mechanism additionally connecting one of said cross elements with one of said toggle links remote from said cross elements.

5. A scissors jack comprising a base member, a top member, a pair of laterally spaced cross elements disposed between said members, upper and lower pairs of toggle links having their inner ends pivoted to said cross elements and their outer ends pivoted to said members, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a crank mechanism additionally connecting one of said cross elements with one of said toggle links adjacent one of said members.

6. A scissors jack comprising a base member, a top member, a pair of laterally spaced cross elements disposed between said members, upper and lower pairs of toggle links having their inner ends pivoted to said cross elements and their outer ends pivoted to said members, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a crank mechanism additionally connecting each of said cross elements with one of said toggle links remote from said cross elements.

7. A scissors jack comprising a base member, a top member, a pair of laterally spaced cross elements disposed between said members, upper and lower pairs of toggle links having their inner ends pivoted to said cross elements and their outer ends pivoted to said members, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a pair of crank mechanisms, one crank mechanism connecting one of said cross elements with one of said toggle links adjacent said base member, and the other crank mechanism connecting the other of said cross elements with another of said toggle links adjacent said top member.

8. A scissors jack comprising a base member, a top member, a pair of laterally spaced cross elements disposed between said members, upper and lower pairs of toggle links having their inner ends pivotedto said cross elements and their outer ends pivoted to said members, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a crank mechanism additionally connecting one of said cross elements with one of said toggle links remote from said cross elements, said crank mechanism comprising a shaft operatively connected to said linkage adjacent one of said members, a crank arm connected to said shaft, and a pitman connecting said crank arm with said operating device.

9. A scissors jack comprising a base member, a top member, a pair of laterally spaced cross elements disposed between said members, upper and lower pairs of toggle links having their inner ends pivoted to said cross elements and their outer ends pivoted to said members, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a pair of crank mechanisms, one crank mechanism connecting one of said cross elements with one of said toggle links adjacent said base member, and the other crank mechanism connecting the other of said cross elements with another of said toggle links adjacent said top member, each crank mechanism comprising a shaft operatively connected to said linkage adjacent one of said members, a crank arm connected to said shaft, and a pitman connecting said crank arm with said operating device.

10. A scissors jack comprising a base member, and a top member each carrying two pairs of spaced pivots thereon, forward and rearward laterally spaced cross elements disposed between said members and having spaced pivots thereon, forward and rearward pairs of lower links interconnecting said base member pivots and said forward and rearward cross element pivots respectively, forward and rearward pairs of upper links interconnecting said top member pivots and said forward and rearward cross element pivots respectively, an operating device, operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a crank mechanism additionally and operatively connecting one of said cross elements with one of said links through one of said pivots.

11. A scissors jack comprising a base member, and a top member each carrying two pairs of spaced pivots thereon, forward and rearward laterally spaced cross elements disposed between said members and having spaced pivots thereon, forward and rearward pairs of lower links interconnecting said base member pivots and said forward and rearward cross element pivots respectively, forward and rearward pairs of upper links interconnecting said top member pivots and said forward and rearward cross element pivots respectively, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and

a. crank mechanism additionally and operatively connecting one of said cross elements with one of said links through one of said pivots, said crank mechanism comprising a crank arm rigidly connected to one of said member pivots, said last-mentioned pivot being rigidly connected to said last-mentioned link, and a pitman connecting said crank arm with one of said cross element pivots.

12. A scissors jack comprising a base member and a top member each carrying two pairs of spaced pivots thereon, forward and rearward laterally spaced cross elements disposed between said members and having spaced pivots thereon, forward and rearward pairs of lower links interconnecting said base member pivots and said forward and rearward cross element pivots respectively, forward and rearward pairs of upper links interconnecting said top member pivots and said forward and rearward cross element pivots respectively, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a pair of crank mechanisms, one crank mechanism connecting one of said cross elements with one of said lower links through one of said base member pivots, and the other crank mechanism connecting the other of said cross elements with one of said upper links through one of said top member pivots.

13. A scissors jack comprising a base member and a top member each carrying two pairs of spaced pivots thereon, forward and rearward laterally spaced cross elements disposed between said members and having spaced pivots thereon, forward and rearward pairs of lower links interconnecting said base member pivots and said forward and rearward cross element pivots respectively, forward and rearward pairs of upper links interconnecting said top member pivots and said forward and rearward cross element pivots respectively, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a pair of crank mechanisms, one crank mechanism connecting one of said cross elements with one of said lower links through one of said base member pivots, and the other crank mechanism connecting the other of said cross elements with one of said upper links through one of said top member pivots, said last-mentioned base member pivot and top member pivot being rigidly connected to their respective lower and upper links.

14. A scissors jack comprising a base member and a top member each carrying two pairs of spaced pivots thereon, forward and rearward laterally spaced cross elements disposed between said members and having spaced pivots thereon, forward and rearward pairs of lower links interconnecting said base member pivots and said forward and rearward cross element pivots respectively, forward and rearward pairs of upper links interconnecting said top member pivots and said forward and rearward cross element pivots respectively, an operating device operatively interconnecting said cross elements and arranged to move said cross elements toward one another, and a pair of crank mechanisms, one crank mechanism connecting one of said cross elements with one of said lower links through one of said base member pivots, and the other crank mechanism connecting the other of said cross elements with one of said upper links through one of said top member pivots, each crank mechanism comprising a crank arm rigidly connected to one of said member pivots, said last-mentioned member pivots being rigidly connected to its respective link, and a pitman connecting said crank arm with one of said cross element pivots.

WM. P. BROWN.

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

UNITED STATES PATENTS Number Name Date 4,399,736 Benjamins Dec. 3, 1921 =.1,526,767 Benjamins Feb. 1'7, 1925 i-1,954,558 Conrad Apr. 10, 1934