US3436947A

US3436947A - Method of manufacturing jack element

Info

Publication number: US3436947A
Application number: US624280A
Authority: US
Inventors: William J Steppon
Original assignee: Ryerson and Haynes Inc
Current assignee: Ryerson and Haynes Inc
Priority date: 1966-02-07
Filing date: 1967-03-20
Publication date: 1969-04-08
Anticipated expiration: 1986-04-08

Description

April 8, 1969 w. J. STEPPON 3,436,947

METHOD OF MANUFACTURING JACK ELEMENT Original Filed Feb. 7, 1966 Sheet of 2 I6 3 INVENTOR T WI IAM J. ST PPON ATIQRNEE April 8, 1969 w. J. STEPPON METHOD OF MANUFACTURING JACK ELEMENT Sheet Original Filed Feb. 7, 1966 INVENTOR WILLIAM J. STEPPON ATTQRNEYS trite tates US. Cl. 72-339 4 Claims ABSTRACT OF THE DISCLOSURE A method of manufacturing a channel shaped element having a convex surface defined at an end thereof from the material of the element wherein the convex surface is substantially tangential to the base portion of the channel configuration. Such formed channel elements are suitable among other uses, for use in scissor jacks wherein the convex surface is utilized for bearing purposes.

Cross-references to related applications The present application is a division of my copending United States application Ser. No. 525,588, filed Feb. 7, 1966, now Patent 3,317,187.

Background of the invention The field of the invention pertains to the formation of channel shaped elements from fiat sheet stock by cutting and bending operations. The sheet stock is first cut to form a blank of the desired configuration, and the blank is then folded in the longitudinal direction at spaced locations to define a channel shape. Appropriate forms are produced which result in the convex bearing surface, and

supporting surfaces for the bearing surface are defined on the blank prior to bending.

In the formation of links for jack elements it has been conventional to form the elements by a pair of spaced parallel linkages interconnected by spacers and fasteners, usually pivot pins. The elements associated with the jack load rest are normally pivoted to the load rest. However, in some jack constructions one of the linkages is connected to the load rest by means of a lost motion arrangement. Lost motion connections are often expensive to manufacture and assemble. Additionally, as high pressures and forces are imposed upon jack linkages and pivots, failure may occur where the links are fixed to the load rest, or in the links itself.

As previously stated, the most common construction for scissor jack element linkages consists of a pair of elongated elements defining each linkage, which are maintained in space parallel relationship by spacers, fasteners or pivot pins. Such linkages are capable of transmitting high forces in the plane of the elements. However, lateral forces imposed upon the linkages will often cause the elements to bend, which may become a serious safety hazard,

in that scissor jacks are often employed to elevate vehicles during the changing of tires.

Summary of the invention The invention pertains to the method of forming a channel shaped element, which may be utilized in a scissors jack, or other environment, wherein an end of the element is provided with a convex surface substantially tangential to the base portion of the element. When employed with a scissors jack, an element formed in accord With the method of the invention utilizes the convex end surface as a hearing which slidably engages the underside of the jack load rest.

The channel shaped element in accord with the invention is formed from a planar blank wherein the end of the blank is shaped While in its planer configuration. After the desired configuration of the blank is achieved, such as by a stamping operation, the blank is bent into a cross sectional channel configuration. After the channel configuration is formed the element is bent adjacent the end to produce the convex bearing surface.

The arcuate convex portion of the element is formed from the base portion of the channel configuration and cooperates with locating and supporting surfaces or notches defined upon the leg portions of the channel configuration. In this manner the convex portion is tangential to the base portion, when viewed in the longitudinal direction, and the convex portion is supported adjacent its free end upon the element leg portions. The convex portion may be so formed as to directly engage the locating notches upon the leg portions, and a Welding operation or other type connection is not necessary to insure engagement of the convex portion with the leg portions.

Brief description of the drawing While the method of manufacturing a channel shaped element in accord with the invention is not limited to the use of forming jack elements or links, for the purpose of illustration and comprehension the invention will be described in this environment. Thus, the purposes of the invention arising from the details and relationships of the components of an embodiment thereof constructed in accord with the method of the invention will be apparent from the following description and accompanying drawings wherein:

FIG. 1 is an elevational, perspective view of a scissors jack in accord with the invention shown in the partially elevated position, portions of the structure being cut away for purposes of illustration,

FIG. 2 is an elevational view of a scissors jack in accord with the invention when fully retracted, a portion of the load rest mounting linkage being cut away to illustrate the relaionship of the load rest to the pivot stud,

FIG. 3 is an enlarged, detail, elevational, sectional view of the load rest and associated links during elevation in accord with the invention,

FIG. 4 is a side elevational view of the formed channel jack link in accord with the invention,

FIG. 5 is a plan view of the link of FIG. 4,

FIGS. 6, 7 and 8 are elevational, sectional views taken through the link of FIG. 4 along sections VIVI, VII VII, and VIII-VIII, respectively,

FIG. 9 is a plan View of the end of the blank from which the channel-shaped link of FIG. 4 may be formed, prior to folding of the blank, and

FIG. 10 is an elevational, detail view of a modification of pivot pin receiving opening and throat defined in a yoke portion.

Description of the preferred embodiment In order to appreciate the manner in which'the convex surface of a link formed in accord with the method of the invention may be practically utilized, the link element is shown and described as incorporated into a scissors jack of the type illustrated. The jack includes a base preferably formed of a sheet material fabricated by a stamp ing and bending operation. The base 10 includes a substantially horizontally disposed portion 12 from which depends vertically extending spaced wall portions 14. A pair of spaced,

parallel pivot pins

16 and 18 are mounted on the base wall portions 14 and extend thereacross. The pivot pin 16 serves as the support for the jack link and the pivot pin 18 supports the jack link 22. The link 20 and the link 22 each consists of a pair of spaced, parallel, stamped

metal elements

24 and 26, respectively, having a lower end through which the associated pivot pin extends. The pivot pins are each provided with a sleeve spacer 28 circumscribing the central region of the pivot pin to maintain the spacing and separation of the elements of a common link. As is the usual practice, the lower ends of the link elements of the

links

20 and 22 are each provided with meshing gear teeth 30, whereby pivoting of the links with respect to the base 10 is controlled, and the

links

20 and 22 will pivot in an equal manner relative to the base during operation of the jack.

The jack also includes a link 32 and a link 34, each having an upper end and a lower end. The link 32 consists of a pair of stamped, parallel elements 36 and the link 34 is of a channel transverse cross-sectional configuration which will be more fully described later. The lower end of the link 34 is formed as a yoke defined by a pair of spaced link portions 38.

The upper ends of the link elements 24 are pivotally mounted upon pivots 40 extending from opposite ends of a block 42 interposed between the link elements, FIG. 1. In FIG. 1 only one of the pivots 40 is shown, in that the other extends away from the viewer. The lower end of each of the link elements 36 is provided with a hole through which a pivot 40 extends, and the pivots 40 are swaged at 44 to maintain the link elements 24 and 36 thereon in a pivotal manner.

The link elements 26 are pivotally mounted upon pivots 46 extending from the end surfaces 48 of a block 50. Also, the yoke portions 38 of the link 34 are disposed adjacent the block surfaces 48 and are formed with an opening for receiving the pivots 46. In this manner it will be appreciated that the upper end of the link 20 is pivotally connected to the lower end of the link 32, and the upper end of the link 22 is connected to the lower end of the link 34.

The block 50 is provided with a bore through which the cylindrical shank 52 of an adjusting screw 54 extends. The adjusting screw 54 has a hexagonal head 56 defined on the outer end thereof, and a thrust bearing is interposed between the head 56 and the block 50. The thrust bearing, preferably, consists of a pair of steel washers 58 having a nylon washer 60 inserted therebetween. The adjusting screw shank portion 52 may be staked, or otherwise provided with means disposed adjacent the inside of block 50, to prevent axial movement of the adjusting screw relative to the block but permit rotationof the screw relative thereto. The block 42 includes a threaded bore 62 through which the threaded portion of the screw shaft 54 extends.

The link elements 36 pass on each side of the link 34 and a pivot stud 64 extends through holes in the link elements 36 and the link 34 to pivotally connect the

links

32 and 34 together.

The upper end of the link 32 is provided with a pivot pin 66 upon which the channel-shaped load rest 68 is pivotally mounted. The load rest 68 includes a base portion 70 from which depends side portions 72 which are in spaced, parallel relation to each other. The load rest base portion 70 is of a nonplanar, concave configuration, as will be apparent from FIG. 3, and includes a convex undersurface 74 adapted to be slidingly engaged by the upper end of the link 34. The load rest base portion 70 is of a configuration wherein when the ends of the load rest are substantially horizontally related, the lowermost portion of the base portion underside as represented at 76 occurs well toward the pivot pin 66 with respect to the right load rest end, FIG. 3. The purpose of the convex configuration of the load rest surface 74 is to increase the elevation of the load rest base portion as the jack approaches its maximum elevation, and this operation will be more fully described later in the specification.

With some vehicles it is desirable that a frame engaging saddle be afiixed to the load rest, and such a saddle is shown in dotted lines in FIG. 3. The saddle 78 may be of sheet material and includes a groove 80 in which a rib or projection defined on the underside of the vehicle body may be received.

The link 34 is of a channel-shaped, transverse cross section including a base portion 82 from which depends lateral side portions 84 terminating in side edges 86. A longitudinally extending depression is, preferably, formed in the base portion 82 for increasing the resistance of the link to bending. The link side portions 84 are each formed with a hole 83 intermediate the ends of the link for receiving the pivot stud 64. Adjacent each of the holes 88 defined in the side portions, the side portions are deformed outwardly at 90 to define outer edges which serve to space the link elements 36 when the jack is assembled.

The lower end of the link 34, as previously mentioned, is defined by a yoke formed from extensions of the side portions 84 to form yoke portions 38 which are outwardly related to the side portions 84. Each of the yoke portions 3-8 is formed with an end edge 92 and a lower edge 94 which lies on the same plane as the side portion edges 86. An opening 96 is defined in each of the yoke portions 38 and is preferably of a circular configuration capable of receiving a pivot 46 of the block 50. A slot, or throat 98, is defined in the yoke portions 38 intersecting the end edge 92. The throat 98 is of a normal transverse dimension capable of slidably receiving the pivots 46- whereby the yoke may be assembled to the block 50. After the yoke side portions 38 have been slipped over the pivots 46, the yoke is deformed by swaging, or similar operation, in a direction indicated by the arrows 100, FIG. 4, to reduce the transverse dimension of the throat 98 to such a dimension as to prevent the pivots 46 from leaving the openings 96 and entering into the throat whereby the yoke could be removed from the pivots. After the yoke portions 38 have been deformed, the yoke will be permanently connected to the pivots 46, yet a pivot interconnection between the link 34 and the block 50 will be maintained as the pivots will be rotatably received within the circular openings 96.

As the upper end of the link 34 is adapted to slidingly engage undersurface 74 of the load rest base portion 70, the link upper end is provided with a convex bearing surface 102 which is capable of engaging the load rest undersurface without galling or otherwise damaging the load rest. To provide the convex bearing surface at the upper end of the link 34, a portion of the link member base portion 82 is arcuately bent from the general plane of the base portion in the direction of the side portions 84. The side portions 84 are each formed with a longitudinally extending shoulder 104 immediately adjacent their ends 106 which is substantially parallel to the general plane of the base portion, and a surface 108 is formed in each side portion which intersects the shoulder 104. The surface 108 is perpendicularly disposed to the longitudinal length of the link, and is located inwardly of the associated end 106 of the side portion a distance substantially corresponding to the thickness of the portion of the base portion which is bent toward the side portions. The end 110 of the bent base portion 112 engages the shoulders 104, and the underside thereof engages the surfaces 108 whereby the relationship which will be apparent from FIGS. 3, 4 and 8 is produced. It

will be noted that portion 112 is of a Width adjacent its end 110 equal to the normal width of the link 34. In this manner the convex portion 112 is firmly supported and will maintain its arcuate form to define bearing surface 102 even under heavy loads.

A manner of forming the upper end of the link member 34 is illustrated in FIG. 9. The link 34 may be formed from flat sheet steel which is folded to the channel-shaped configuration of the link. When the link 34 is formed in this manner, the arcuate end thereof is formed as shown in FIG. 9 prior to the link being bent into the channel shape. Prior to forming the end of the link, the link blank 114 would have a rectangular end configuration as represented by the dotted lines 116, FIG. 9. The blank 114 is placed within a die and is notched adjacent the end on both sides of the blank central region to define a pair of notches 118. The notches 118 form parallel surfaces 120 which define the maximum width of the tongue 122. Surfaces 124 define the minimum width of the tongue, and the

surfaces

120 and 124 on each side of the tongue are interconnected by an inclined surface 126. Arcuately formed surfaces 128 intersect the surfaces 124 and intersect the surfaces 108 which are perpendicularly disposed to the longitudinal axis of the blank. The shoulder surfaces 104 are disposed parallel to each other and to the longitudinal axis of the blank. The ends of the side portions are defined by the surfaces 106, as described above, and the end of the tongue constitutes end 110. After the blank is shaped as shown in FIG. 9, the blank is folded along longitudinally extending dotted lines 130 to the channel configuration, whereby the side portions 84 are disposed in a substantially parallel relation on a common side of the general plane of the central base portion 82. The tongue 122, which forms base portion 112, is then bent toward the shoulders 104 to engage the shoulders 104 and surfaces 108, as shown in FIGS. 3, 4 and 8. The formation of the convex link end does not require welding or other secondary operations after the portion 112 is bent into engagement with the shoulders 104 and surfaces 108. As will be apparent from FIGS. 5 and 8, the width between the surfaces 120 corresponds to the width of the link end and a clean appearing and effective convex bearing surface is provided which is capable of withstanding the loads which will be imposed thereon during ordinary service.

Extension and retraction of the jack is produced by rotating the screw 54 by means of a wrench applied to the hexagonal head 56. Normally, the threads of the screw will be of a right hand whereby clockwise rotation of the screw draws the

blocks

42 and 50 toward each other to extend the jack and raise the load rest 68 relative to the base 10. When the screw 54 is rotated the maximum degree in the counterclockwise direction, the jack will assume the retracted and compact relationship shown in FIG. 2. In FIG. 2 a portion of a link element 36 is broken away to illustrate the presence of the notch 132 defined in each of the side portions 72 of the load rest which provides clearance for the pivot stud 64 and the outwardly formed spacer deformations 90 formed on the link 34 adjacent the pivot stud holes 88.

As the jack is extended from the position shown in FIG. 2 toward the extended position, it will be appreciated that the link 34 will slide relative to the load rest 68. In the fully retracted position of FIG. 2, the convex end of the link 34 extends substantially beyond the load rest and as the jack is extended, the load rest undersurface 74 will slide along the link base portion 82. As the jack approaches its maximum extension, the arcuate, convex bearing surface 102 will engage the load rest undersurface 74, as shown in FIG. 3. Preferably, the undersurface 74 is lubricated to minimize the friction between the load rest undersurface and the convex bearing surface. Further extension of the jack from the position shown in FIG. 3 causes the convex bearing surface 102 to approach and ride on the downwardly depressed portion 76 of the load rest base portion as the convex bearing surface approaches the pivot pin 66. The downwardly depressed portion 76 will cause an increased counterclockwise pivoting of the load rest 68 about the pivot pin 66, FIG. 3, in an upward manner even though little relative sliding movement between the convex bearing surface and the load rest undersurface takes place. Thus, the presence of the downwardly defiected load rest portion 76 permits an extra elevation of the load rest 68 which would not be possible if the load rest base portion were of a planar configuration.

In FIG. 10 a modification of the formation of the pin receiving opening and throat defined in the yoke portions 38 of the link 34 is shown. In FIG. 10 the pivot pin circular opening 134 is located with respect to the associated yoke portions at the same location as the embodiment of FIG. 4. However, the pin receiving slot or throat 136 defined by the surfaces 138 intersects the lower edge 94' of the yoke portions 38', rather than the end 92 thereof, as in the embodiment of FIG. 4. The yoke employed in the embodiment of FIG. 10 is placed on the pivots 46 in the same manner as previously described and after assembly to the pivots 46, the yoke portions 38' are subjected to a force as indicated by the arrow to reduce the dimension of the space separating the throat surfaces 138 and, thus, retain pivots 46 within the circular openings 134.

It will be appreciated that in accord with the invention the link 34 has high strength characteristics. By utilizing the channel-shaped configuration, high resistance to bending of the link 34 is achieved even though the link may be formed of #7 gauge hot rolled sheet steel. The yoke construction at one end of the link permits the link to be readily afiixed to the pivots of the block 50 and the pivot receiving openings and throat defined therein simplify assembly. The construction of the integral convex bearing surface 102 reduces fabrication costs, in that extra material is not required and, yet, an effective nongalling, convex bearing surface is achieved. The support of the bearing surface on the shoulders 104 and surfaces 108 adequately supports the convex bearing surface defining portion 112, and scissor jacks constructed in accord with the invention have continued to operate successfully well beyond the required number of cycles during life determination tests.

It is appreciated that various modifications to the disclosed embodiment may be apparent to those skilled in the art without departing from the spirit and scope thereof, and it is intended that the invention be limited only by the following claims.

I claim:

1. The method of forming an elongated element having a transverse cross section of a channel configuration including a central base portion, side leg portions and a convex bearing surface adjacent an end from an elongated fiat blank having a longitudinal axis, a central portion, side portions disposed on each lateral side of said central portion and an end, comprising the steps of notching the blank side portions adjacent to and intersecting the end thereof on each lateral side of the longitudinal axis of the blank to define a centrally disposed cantilever supported tongue having a longitudinal length parallel to the blank axis and an end transversely related to the tongue length, and defining a longitudinally extending projection upon each blank side portion on each side of said tongue, said tongue having a greater longitudinal length than said projections, forming a shoulder facing said tongue and transversely disposed to the end of said tongue in each of said projections and at an axial location on said blank intermediate the tongue end and the axial depth of said notches, longitudinally folding said blank at the axial regions of association of said side portions with said central portion whereby said side portions are disposed on a common side of said central portion and are spaced apart a distance less than the transverse width of said tongue adjacent the end thereof, and bending said tongue in an arcuate convex manner in the direction of said folded side portions to engage the tongue end with said side portion shoulders.

2. A method of forming an elongated element as in claim 1 wherein the end of said tongue is formed perpendicular to the blank longitudinal axis and said shoulders are formed parallel to the blank longitudinal axis.

3. The method of forming an elongated element as in claim 2 comprising the step of forming a locating surface on each of said projections perpendicular to the axis of said blank and intersecting said shoulder formed on the associated projection whereby said locating surfaces locate the tongue end on said shoulders when bent into engagement therewith.

4. The method of forming an elongated element as in claim 1 comprising the step of folding said blank at the axial regions of association of said side portions with said central portion such that said side portions are substantially parallel to each other.

References Cited UNITED STATES PATENTS Re 16,806 12/1927 Reeves 254-126 2,765,525 10/1956 ONeill 113-116 FOREIGN PATENTS 588,576 5/1925 France. CHARLES W. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner.