US 2636770 A
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L 0 S 7 W 7 RR n e mom 3 7, Nc l70 6 s |||I| I l l I l I l I I l l ||IJ E 9m, B VW T A NH A a I IK E m PIM. f m s F V l l l l l l l I l l I nlm Tmf G .N I L m N o L 5 m m R m m 8 P o www c. m d 1 S 6 Kfm n T Y F m v, C Q m A [.II G .lx1 w m W 88 3 m L 1 8, 2 M m m g .n F p A Patented Apr. 28,` 1953 LIFTING AND CARRYING CLAMP FOR HANDLING STONE SLABS Ted Keith Cornwell, Cold Spring, Minn., assignor to Cold Spring Granite Company, Cold Spring, Minn., a corporation of Minnesota Application December 8, 1950, `Serial N o. 199,856
1 Claim.l (Cl. 294-103) This invention relates to a lifting and carrying clamp for handling stone slabs.
It has been a considerable problem in erecting and handling large stone slabs such as marble for stone veneering and the like to provide efflcient means for securely holding the gripping apparatus on the slab without damaging the highly polished surface or causing breakage of the slab and while permitting the slab to be lowered and placed directly into the desired position whilestill being supported from a iieXible overhead supporting element.
It is an object of my invention to provide a slab lifting and erecting gripping clamp particularly adapted for use with highly polished hard-surfaced stone slabs and adapted to be supported from an overhead flexible hoist element and to be lowered thereby into the desired position.
It is another object to provide a slab-erecting clamp particularly adapted for use with highly polished hard-surfaced stone slabs and having a clamping jaw element with a slightly compressible stone-engaging surface fixed thereto and underlying a reinforcing pressure-applying element to equally distribute the clamping pressure over the relatively soft gripping surface.
More specifically, it is an object to provide a gripping clamp having a connector element adapted to be attached to a iiexible overhead supporting member and having a stationary gripping element for engagement in a cooperating recess or slot provided in the rear unpolished side of a stone slab and a clamping jaw element having a reinforcing pressure-applying outer member with a slightly compressible polished surface-engaging gripping element underlying said pressure-applying element and producing sufcient friction against said highly polished surface to permit suspension of the slab solely by means of the gripping clamp alone to facilitate erection of the slab.
It is the combination of a shiftable, relatively large area gripping jaw having a rigid pressureapplying backing member with an underlying, slightly compressible gripping surface fixed thereto with a clamp having an upstanding attachment element for connection with an overhead fiexible supporting member which permits a stone slab such as granite or marble to be tightly gripped along only the top marginal edge portion which facilitates the handling and erection thereof.
The above and other objects and advantages of the invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which:
Fig. 1 is a perspective View of my new gripping clamp in full lines showing a stone slab gripped thereby and supported for erection be ing shown in dotted lines;
Fig. 2 is a transverse vertical sectional View showing a stone slab securely gripped between the jaws of my gripping clamp with the over-t head support member `connected therewith.
As illustrated in the accompanying drawings, a gripping clamp, which in the form shown has a rigid, inverted, substantially U-shaped body '5, is provided, having` the rear arm 5a and the front arm 5b rigidly interconnected by the supporting element 5c. A stationary gripping jaw having the diminished` projection 6 is fixed to the rear arm 5a and is adapted to engage the rear side of a slab such as the rear unpolished side of a slab T. The slab has a recess or slot formed in the rear surface of the upper marginal edge portion and the diminished projection 6 of the stationary gripping jaw is constructed t0 be received in said recess.
A shiftable clamping jaw 8 is mounted on an elongated shiftable shank such as the threaded shank 9 which is threadably received. through the front arm 5b as best shown in the accompanying drawings. The clamping jaw 8 is laminated with two layers being formed thereon. An outer pressure-applying layer in the shape of a disc 8a which is made from any suitable rigid material such as steel, wrought iron, or the like of sufiicient thickness to uniformly distribute the pressure applied by turning the screw shank 9 through the arm 5b. A relatively soft. slightly compressible lamination 8b is fixed under disc 8a and is substantially co-extensive therewith to engage the highly polished front surface of the slab l. A relatively soft metallic material is preferably used for this lamination 8b such as lead or Babbitt material. The backing pressure applying element permits a suiiicient surface area of relatively soft gripping material to be provided to prevent injury to the slab surface and to prevent possible cracking of the slab when gripping pressure is applied thereto.
An attachment ring I0 is connected to the supporting element 5c and is adapted to receive a hook ll carried by a depending flexible supporting member such as the chain I2 which is, of course, connected with any suitable hoisting means such as a conventional block and tackle (not shown).
After long experimentation with the proper material to use for the engaging surface of the movable jaw, I found that a soft metallic material such as lead produced surprisingly .satisfactory results. 'is the 'slightly compressible f'quality of this surface-engaging jaw that gives it its high frictional resistance without damaging the highly polished surface or causing possible cracks in the veneered slab. v y
It Will be seen that I have provided f'a 'relatively simple yet highly efficient lifting and vcarrying clamp for gripping stone slabs to Afacilitate han* dling and erection thereof. 4My clamp is provided With an attachment element adapted to be quickly and easily attachedt'o a hook suspended from an overhead hoisting mechanism and to be supported solely thereby. The general 'combination of the reinforcing backing element with a slightly compre's'sible 'gripping ysurface xed thereto and means ior tightlyclamping 'said compressible surface yagainst the highly polished iront surface of a 'stone slab 'produces a clamp which is adapted to tightly grip and hold a 'stone cuter jaw being provided with a slightly eompressible metallic lgripping surface having a reinforcing `rigid backing element 'xed therebehind to permit secure gripping `of a highly polished stone "surface produces a lifting clamp adapted to greatly facilitate handling Vand erection of stone slabs and materially Aspeeds up erection time, since the slab is suspended solely from the medial upperl marginal edge `portion thereof and permits the sides and bottom edges to `be precisely positioned relative to the other slabs before the slab being erected is released 'from its overhead support. The rear stationary 'jaw `fi is relatively small to permit reception thereof in a 'recess or slot formed in the rear surface of the upper marginal edge `portion of the slab.
` it will, of course, be understood that various changes may be made "in the form, details, arrangement and proportions of the various parts 4 without departure from the scope of my present invention, which, generally stated, consists in the matter shown, and described, and set forth in the appended claim.
What I claim is:
.A lifting and carrying clamp adapted for use in 'handling Fand erecting stone veneering slabs 'for buildings and the Elike having one polished surface on the outer side thereof, said clamp 'comprising a rigid unyielding body member, a relatively thin stationary jaw fixed in depending relation at'the rear end portion of said body and having an outwardly projecting interlocking element ad'apte'd't intert with a cooperating recess formed .in the back side of the slab, a shiftable clamping javv mounted at the outer portion of sai-d body and disposed in opposed relation to said xed clamping jaw and forming the outer front jaw member of the gripping clamp, an unyielding pressure-applying backing vplate on the outer front jaw member vvith a 'slightly Vcompressible relatively soft metallic layer fixed on the backing plate for vclamping engagement against the 'smooth polished `outer slab surface, means mounting said .shiftablecla-inping jaw on said body with provision for forcibly projectingv said front jaw member toward the rear jaw member to tightly vclamp said two jaws against the respective front and rear sides of the upper marginal 'portion of a stone slab to form the sole Vconnection therewith and tightly hold the rear outwardly projecting interlocking element in intertting relation within the cooperating recess in the back side of 'the slab, and an attachment element mounted on an intermediate portion of said body member".
TED KEITH CORNVELL.
References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 291,248 West Jan. 1, 1884 307,453 Galbraith NOV. 4, 1884 '387,109 Sanford July 31, v1888 855,989 Sh'el" t al June 4, 1907 865,444 'staie'y' sept. in, 1907 1,221,400 Wilhelm et al. Apr. 3, 1917 1,535,022 Jenkins i.. Apr. 2l, 1925 FOREIGN PATENTS Number n Country Date 13,305 Norway Feb. 6, 1905