US3862743A

US3862743A - Vertical stress-side load member screw jack

Info

Publication number: US3862743A
Application number: US447760A
Authority: US
Inventors: Richard S Graafsma; R Harlan Nehrig; Nicholas J White
Original assignee: Auto Specialties Manufacturing Co
Current assignee: Ausco Products Inc
Priority date: 1973-06-18
Filing date: 1974-03-04
Publication date: 1975-01-28
Anticipated expiration: 1992-01-28
Also published as: CA983006A

Abstract

A screw jack is disclosed which has a side load member for engaging vehicle suspension parts or other loads at relatively low elevations. The side load member is provided with a bumper and a displaced hook for engaging the load from opposite sides and producing a force couple. The force couple minimizes bending stresses on the jack, thus contributing to jack safety and long service life. A second load engagement point is provided atop the jack for engaging loads at relatively high elevations. If desired, a spring can be interposed between the side load member and the jack body to urge the side load member into an opened position for readily engaging the load. The side load member is attached to the screw member so as to permit the side load member to be tilted, by the spring, into its open position.

Description

Matte bites atet 1 Graaisma et a1.

[ 1 Jan. 28, 1975 VERTlCAL STRESS-810E LOAD MEMBER SCREW JACK [75] inventors: Richard S. Graafsma, Benton Harborr; R. Harlan Nehrig, Stevensville; Nicholas J. White, St.

Joseph. all of Mich.

[731 Assignee: Auto Specialties Manufacturing Company, St. Joseph. Mich.

[22] Filed: Mar. 4, 1974 [21] Appl. No.: 447,760

Related US. Application Data [63] Continuation-impart of Ser. No. 370,793, June 18,

1973, abandoned.

2,176,014 10/1939 Ryerson 2,554,910 5/l95l Jensen 1628,18 l 2 2/1953 Palazzolo 2.743.903 5/1956 Lucker Prinun'y Examiner-Othell M. Simpson Attorney. Agent. or Firm-Olson. Trexler, Woltcrs. Bushnell & Fosse. Ltd.

[57] ABSTRACT A screw jack is disclosed which has a side load member for engaging vehicle suspension parts or other loads at relatively low elevations. The side load member is provided with a bumper and a displaced hook for engaging the load from opposite sides and producing a force couple. The force couple minimizes bending stresses on the jack, thus contributing to jack safety and long service life. A second load engagement point is provided atop the jack for engaging loads at relatively high elevations. If desired, a spring can be interposed between the side load member and the jack body to urge the side load member into an opened position for readily engaging the load. The side load member is attached to the screw member so as to permit the side load member to be tilted, by the spring, into its open position.

13 Claims. 11 Drawing Figures VERTICAL STRESS-SIDE LOAD MEMBER SCREW JACK CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of copending application Ser. No. 370,793 filed June 18, 1973, now abandoned.

BACKGROUND OF THE INVENTION This invention relates generally to screw jacks and more particularly concerns screw jacks adapted to engage a load which may be initially located either above or below the jack top.

Screw jacks, such as those in U.S. Pat. Nos. Re. 17,527, 2,731,232, 2,750,150 and 3,118,651, have long been known as safe and powerful mechanisms for engaging and lifting heavy loads. Motorists are familiar with screw jacks which are adapted to engage'car or truck bodies or suspension parts. By appropriate manipulation, the vehicle can be lifted temporarily, thereby permitting a flat tire to be changed or other repair work to be done on the vehicle underside.

Often a screw jack is placed on pavement or firm ground at a spot directly underneath a designated portion of a vehicle body or suspension system. This jack placement requires, of course, that sufficient clearance be available between the supporting ground and the designated jack engagement point on the vehicle.

Developments in suspension system design have led to the use of different suspension mechanisms at front and rear vehicle wheels. Some modern suspension systems have front end components which are located relatively near the ground, especially when the associated tire is deflated. Thus, jacks adapted for use with this part of the vehicle must be able to initially engage the front end A frame or related part at an engagement point which may be located relatively close to the ground.

Conversely, however, these same suspension systems have rear end components located relatively high above the ground. Thus, jacks adapted for use with this part of the vehicle must be able to engage the rear axle or a related part at an elevated point. Further, the jack must be able to raise the engaged point and vehicle to an even higher work level with safety.

Some previous commercial screw jacks have been too tall, even in their most retracted position, to fit between the ground and a front end A frame member or similar desired engagement point. Other screw jacks, while able to engage a front end jacking point, have been too short, even when fully extended, to lift a rear end axle or similar jack engagement point to a convenient work height.

It is well known that some jacks and jacking methods contemplate engaging the vehicle body by the jack. Often, jack engagement points located on the body are easily accessible, and front and rear engagement points are located at roughly equal distances above the ground. However, such jacking schemes require lifting the body to a relatively high work position to compensate for suspension drop and to present the wheel or other suspension parts at an acceptable working height.

It is thus the general object of the present invention to provide a safe and sturdy screw jack for use with loads which must be initially engaged at either a relatively low or a relatively high engagement point. The

general object, in other words, is to provide a screw jack which can be used with either the front end or the rear end of a modern motor vehicle suspension system.

Another general object of the invention is to provide a screw jack which minimizes bending forces applied to the screw mechanism and other jack parts. A related object is to provide a screw jack having a long service life and requiring a minimal operating effort.

It is also an object to provide a powerful and safe screw jack capable of engaging a load at a relatively low initial engagement point, or alternatively capable of initially engaging a load at a relatively elevated point, and then lifting the engaged load to a convenient work height in a safe manner.

Yet another object is to provide a jack which is adapted to readily and easily engage loads at either engagement point without extensive preliminary jack manipulation.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the description, like reference numerals refer to like parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a perspective view showing the jack of the present invention in its general aspect as it appears when engaging a suspension system component of a typical vehicle;

FIG. 2. is a side elevational view of the jack shown in FIG. 1 taken substantially in the plane of line 2-2 in FIG. 1;

FIG. 3 is a front elevational view of the novel jack;

FIG. 4 is a rear elevational view of the novel jack showing, in partial section, portions of the internal jack operating mechanism;

FIG. 5 is a top plan view of the novel jack;

FIG. 6 is a front elevational view of an alternate embodiment of the jack;

FIG. 7 is a top plan view of the alternate embodiment of the jack;

FIG. 8 is a side elevational view similar to FIG. 2 showing an alternate embodiment of the jack as it appears befor engaging a load;

FIG. 9 is a side elevational view similar to FIG. 8 showing the alternate jack embodiment as it appears after engaging the load;

FIG. 10 is a fragmentary cut away view showing the interconnection between the jack load member and a supporting jack screw member; and

FIG. llll is a sectional view taken substantially in the plane of line llllll in FIG. 10.

DETAILED DESCRIPTION While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention. By way of specific example, it will be understood that the present invention can be adapted for use with other forms of jacks such as hydraulic jacks; for illustrative purposes, however, the invention will be shown as it is embodied with a screw jack mechanism.

Turning more specifically to the drawings, there is shown a jack l0 embodying the present invention. In

general, this jack includes a base member 12, which can be considered to comprise a housing member 13 and a plate member 14 adapted to provide a firm supportive foundation upon underlying pavement or ground. As shown in FIG. 4, the housing member 13 carries one or more members 15 for extension or retraction, which may be screw members.

The jack is operated by a handle 17 (see FIG. 2) which rotates a pinion gear 18. The turning pinion gear 18 causes rotation of an engaged crown gear 19 mounted, as by a bearing 20, upon the base plate 14. The crown gear 19 in turn drives the screw member 15, causing its extension or retraction relative to the housing member 13. g

In accordance with the invention, the novel jack is adapted to engage a load at a relatively low initial engagement point, and to lift it with minimum bending stresses being imparted to the jack. As illustrated in FIG. 1, the load is represented by an A frame member 23, which mounts a wheel 24 on a motor vehicle frame 25 by means of appropriate springs 26 and pivots 27. The low load engagement capability of the jack 10 is provided by a side load member 30 which is attached to a head 31 of the screw member and extends downwardly toward the jack base plate 14. For engaging the load 23, the side load member 30 includes a hook means 32 and a bumper means 33. Thus, as illustrated in FIG. 1, the jack 10 need not be located directly under the A frame 23 in order to lift it. Rather, the jack 10 can be located to one side of the load; moreover, the jack 10 can be of a height greater than the elevation of the load above the underlying ground.

It has been found that, in operation, jacks utilizing side load members often incur severe bending stresses in the screw members and other parts. Minimization or elimination of these bending stresses reduces internal jack friction, and in turn reduces the effort required to operate the jack handle and extends the jack service life. In accordance with the invention, therefore, the hook means 32 is formed to engage the load 23 at a first location A, as shown in FIG. 2. It will be noted that the force imparted by the load to the hook means 32 can be represented by a vector arrow X; the vector can be resolved into a number of vector components, one being oriented in a direction perpendicular to the screw member, as represented by the arrow X.

The bumper means 33 is spaced apart from the hook 32 in an axial direction relative to the screw member by an interconnecting strut 34. The bumper 33 similarly engages the load 23, but from an opposite side at a second location B, and receives a force which can be represented by a vector arrow Y. In an analysis like that used with the hook, the vector Y can be resolved into a number of components, one being oriented in a direction perpendicular to the screw member, as represented by the force vector arrow Y.

It will be noted that the force vector Y is imparted to the side load member in a direction opposite to the first vector component X. In accordance with this aspect of the invention, a force couple is created which tends to minimize, if not neutralize, bending forces imparted to the screw member 15 and other jack parts. Neutralization of this side load bending moment also reduces the possibility of jack tipping and vehicle rolloff. In the embodiment illustrated in FIGS. 3 and 5, the bumper 33 is formed of two spaced apart

members

37 and 38 which are interjoined by a pin 39. Thus, two

spaced apart

bumper feet

40 and 41 are provided to engage the load at horizontally spaced apart locations. Such engagement arrangement provides a firm and rigid load support, and further discourages jack tipover or vehicle rolloff.

As illustrated in FIGS. 6 and 7, it will be understood that firm and rigid load support may also be obtained by forming the hook 51 with a relatively broad horizontal load engaging surface 52. Further, the bumper 53 may be formed with a relatively short horizontal load engaging frontal area 54 which may take the form of a raised pad 55. It will be understood that the bumper pad 55 may be formed to provide a frontal contact area 54 of any desired shape. The side load member 56 thus constructed minimizes, if not neutralizes, bending forces imparted to the jack screw member and other jack parts.

In accordance with yet another aspect of the invention, means are provided for engaging a load at a position atop the jack 10. In the illustrated embodiment, a shallow V-shaped notch 44 is formed in the top of the side load member 30 which conforms to the shape of a vehicle rear axle or like load engagement point. Thus, force loads Z experienced by the jack when engaging a load at the top notch 44 are substantially axially aligned with the screw member 15, and bending forces are again minimized. Since the load is engaged at the top of the jack at a relatively elevated position, however, it can be lifted to a high work location.

As indicated above, the side load member 30 can be attached to the head 31 of the screw member 15. In the illustrated embodiment, this attachment is accomplished by a rivet 39 or other convenient attachment means. Alternatively, the side load member 30 can be attached to the upper extremity of the screw member head 31 by a pin or other pivot attachment means which will permit tilting of the side load member 30 relative to the screw member 15 about a horizontal axis perpendicular to the screw member axis. Such pivoted attachment permits the side load member 30 to tilt or rotate with the load if the vehicle or load should be tipped or begin to roll off the jack. Such side load member tilting permits the vehicle to fall off the jack without twisting the load or damaging the jack or the vehicle.

Another embodiment of the invention especially adapted for easy initial load engagement as illustrated in FIGS. 8 and 9. Here, a biasing member such as a leaf spring 60 is interposed between the side load member 30 and the jack housing member 13. When the jack does not engage a load, this spring 60 tilts the side load member 30 away from the jack housing to position the hook 32 in an opened position to readily engage the load 23. A spring guide tongue 61 is formed at the free end of the spring to engage a top corner 62 of the housing member 13 and position the spring 60 when the jack screw 15 is lowered into the position shown in FIG. 9. For convenience and economy, the bumper 33 and spring 60 can be attached to the side load member I 30 by a common rivet 64.

In carrying out the easy-positioning aspect of the invention, the side load member 30 is mounted to the screw member head 31 by a rivet 6b, as shown in FIGS. 10 and 11. A reduced shank portion 67 is staked or otherwise rigidly secured to the side load member 30, and an elongated shank portion 68 fits through a hole 69 formed in the screw member head 31. Since the elongated shank portion is longer than the head 31 is thick, the rivet 66 can tilt within the hole 69, and the side load member 30 is permitted to undergo its tilting motion between the initial or opened position shown in FIG. 8 and the load-lifting position shown in FIG. 9 without damaging the rivet 66, the screw member 31 or other jack parts. However, the non-circular shape of the rivet shank 68 and mating shape of the head hole 69 prevent rotation of the side load member about the vertical axis of the screw member 15. While the shank and hole shapes here shown are square, it will be understood that rectangular or other shapes could be used to prevent rotation of the load member 30 about the screw member 15. Since internal jack structure (not shown) prevents rotation of the screw member relative to the jack housing 13, the side load member 30 is also prohibited from rotating about the vertical screw member axis. Thus, the side load member 30 is always carried adjacent the same jack housing side 71 opposite the jack-handle-accepting pinion gear 18. This arrangement permits the jack 10 and especially the side load member 30 to be easily positioned adjacent the load 23 for easy initial engagement.

As will be understood from the foregoing description, jack use is simple and straightforward. The jack is first located adjacent or under the intended load as illus trated in FIG. 1. Then a handle 17 is attached to the pinion gear 18, and is appropriately rotated. The engaged load can be easily moved up to or down from a work height.

The following is claimed as invention:

1. A jack adapted to lift a load from a side position, including a base means, a first member at least partially extensible from and retractible into the base means for raising and lowering a load relative to the base means, and a side load member including a portion overlying and resting directly on top of said first member in direct load transferring relationship thereto, the side load member including hook means depending from said portion for engaging the load at a first location and receiving a first force vector component imparted by the load from a direction perpendicular to the extensible and retractible member, and bumper means for engaging the load at a second location and receiving a second force vector component imparted by the load from a direction perpendicular to the extensible and retractible member and opposite to the first force vector component, and axially extending non-load bearing pin means connecting said attachment portion to the upper end of said first member for pivotal movement about a horizontal axis.

2. A jack according to claim 1 wherein said extensible and retractible member is a screw member.

3. A jack adapted to lift a load from a side position, including a base means at least one nonrotatable substantially vertical screw member at least partially extensible from and retractible into the base means for raising and lowering a load relative to the base means, and a side load member attached to the screw member for engaging the load, the side load member including an attachment portion overlying and resting in load transmitting relationship on said screw member, said side load member further including hook means depending from said attachment portion for engaging the load at a first location and receiving a first force vector component imparted by the load from a direction perpendicular to the screw member, and bumper means for engaging the load at a second location and receiving a second force vector component imparted by the load from a direction perpendicular to the screw member and opposite to the first force vector component, and interconnecting means between said screw member and said attachment portion, said interconnecting means including an axially extending fastener element between said attachment portion and screw member and having an excess length for permitting the attachment portion to pivot on top of the screw member about a generally horizontal axis, said fastener element including portions engageable with the screw member and the attachment portion to prevent rotation of the load lifting member around a vertical axis.

4. A jack according to claim 3 wherein said bumper means engages the load at two horizontally spaced apart locations.

5. A jack according to claim 3 wherein said bumper means and said hook means are spaced apart from one another in axial direction relative to said screw memher.

6. A jack according to claim 3 wherein said jack includes means for engaging a load at a position atop the jack and substantially axially aligned with said screw member, thereby permitting engagement of a load by the jack at a relatively elevated location.

7. A jack according to claim 6 wherein said means for engaging a load at a position atop the jack is provided on said side load member.

8. A jack according to claim 3 wherein said screw member includes a head at its upper extremity, and said fastener element extends between said head and said attachment portion which rests on said head, and wherein said bumper means and said hook means are located between said screw member head and the bottom of the jack, thereby permitting engagement of a load by the jack at a relatively low location.

9. A jack according to claim 3 wherein said hook means includes a substantially horizontal load engaging surface.

10. A jack according to claim 3 wherein said bumper means includes a raised pad formed upon said side load member, the raised pad having a frontal contact area for engaging the load and receiving said second force vector component.

11. A jack according to claim 3 including biasing means interposed between said base means and said side load member for urging the side load member into a tilted opened position to readily initially engage a load.

12. A jack according to claim 11 including rivet means permitting the side load member to be tilted between a load-lifting position and an initial opened position.

13. A jack according to claim 12 wherein said fastener element is a rivet fixed to said attachment portion and provided with a non-circular cross-sectional shank portion, said rivet shank portion engaging a mating non-circular aperture in said screw member head to prevent the side load member from rotating about a vertical axis relative to said screw member and said jack base member.

Claims

5. A jack according to claim 3 wherein said bumper means and said hook means are spaced apart from one another in axial direction relative to said screw member.