US2672790A - Clamp - Google Patents

Description

March 23, 1954 w. w. CARROLL CLAMP Filed Oct. 11, 1948 NVEMRT" Patented Mar. 23, 1954 This invention-relates to machine clamps "for use"in"clah1ping the work or fixtures to the platen or table of a machine tool, such as a planer or milling machine. Such platens and tables are commonly'provided with T slotsa dapted to receive-the heads of bolts which extend upwardly above thesurface of the platen or tablefor use in securing thereto either the work itself or a fixture in which the work is clamped. Perhapsthe most frequent arrangement is one in which a bolt extends upwardly from a T-slot througha hole or longitudinal slot in a clamp member one end of which restsolrtheworker fixture to be held and thother end of which rests on a block or stack of blocks of appropriateheight.

It isanobject of my invention to produce a clamp which will not require the use of the block. or stack of blocks just referred to. A further ob ject of the invention is to produce a clamp which, without modification, can be employed to clamp objects of a wide range of thicknesses to a platen or table of a machine tool. Still another object of the invention is to produce a clamp which can be employed to exert clamping pressure against a narrow ledge or shoulder on the object to be held.

In carrying out the invention I provide an elongated, preferably arched, longitudinally slotted clamp arm which may be conveniently, but not necessarily, formed of two parallel members spaced apart to provide the aforesaid slot. At one end of the clamp arm there is pivotally secured thereto a foot adapted to rest on the platen or table of the machine tool, while at the other end there is pivotally mounted a pressure me her or pad adapted to rest on the work. In the preferred form of my invention, the clamp includes means for limiting outward swinging movement of the pressure member or pad to a position in which it forms, in effect, an extension of the clamp arm and is adapted to rest on a narrow ledge or shoulder of the object being clamped. The clamp arm is provided in its upper face with a series of arcuate notches each adapted to receive a cross member. A central opening in the cross member receives a clamp bolt having a head proportioned for reception in the T-slot of a machine-tool. table or platen.

The accompanying drawing illustrates a preferred form of the invention: Fig. l is a side elevation showing the clam in use to hold an object on the table or platen of a machine tool; Fig. 2 is a vertical section on the line i-2 of Fig. l; and 3 is an elevation similar to Fig. 1 showing the clamp adapted for engagement with a nar row ledge or shoulder on the object to be held.

' in the drawing, the lainp mm- 'se'sa 'p or arcliedside members '19 having the samegeuerar 'a'pe esteemed-earallel "to eacli dtliei ht tine end; the mmbe'rs l il are pivbtally oniiteci to after; H adaptedto re'st n the surraceef tasi -orphan l2 of'a m tool. Conveniently; the 'foot 'I I i a "bedivertica'l slots-in which the 'ndsof "l0 rest uveiy reeeitea, and-a I g s" t'l' leu'e'u- "the footai'id -the member's 'l ii to riivide 'th'e therbetvven. 'At" their o hers I it receive between a her or pad i 4 pivetauy duiited as "through i the ss fiirl l5eirtehdingthi'e-iigh the arms I il ahd the pad.

In their upper faces,

the arms H) are provided with series of aligned arcuate notches I? each aligned pair of which is adapted to receive the ends of a cross member 18. The surfaces of the notches IT are circular in form as are also the notch-engaging surfaces of the cross member l3, so that the cross member can rock freely about a horizontal axis in the notches which receive it.

" Between the two members H), the cross member I8 is provided with a transverse opening for the reception of a bolt l9, such bolt being provided above the cross member with a washer 2B and a nut 2i. The lower end of the bolt [9 has a head 22 adapted for reception in any of the T-slots 23 in the platen or table [2.

The manner in Which the clamp is used will be obvious in Fig. 1. The bolt head 22 is placed in the desired T-slot 23, the foot I I is disposed on the table [2, and the pad It is seated on the object 25 which is to be clamped in place on the table I 2. When the nut 2| is tightened, the members ID are urged downwardly about the axis of the pin l3 and the pad I4 is forced firmly against the object 25. The arched shape of the members It adapts them to sustain the bending loads which are applied to them and is frequently of further advantage in enablin th members I0 to clear the edge portion of the object with which the pad I4 i engaged. As will readily be apparent, the clamp may be used without modifi cation to hold objects 25 of a wide range of thicknesses. The series of notches l1 permits the cross member I8 to be placed in a plurality of positions along the members Ill, thus permitting variation in th position of the clamp laterally in respect to the T-slot 23 with which it is associated. Desirably, both hebolt head 2 and th washer 20 have dimensions transverse to the bolt I9 greater than the distance between the two members It, whereby the bolt cannot be removed from association with the remainder of the clamp except by removal of the nut 2|. As a result, all the parts of the clamp are held together when the clamp is not in use.

As will be obvious from Fig. 1, the axis of the pivot pin 15 must lie within the limits of the surface upon which the pad 14 rests, as otherwise tightening of the nut 21 would result in tipping of the pad I4 and it would be impossible to exert the desired clamping efiort on the work. It is sometimes desirable, as in the situation indicated to Fig. 3, to exert the clampin efiort on a ledge or shoulder 25' so narrow that the axis of the pin 15 cannot be disposed within the limits of the ledge or shoulder when the lower surface of the pad 14 en ages it. To adapt the clamp for use in such a situation, I so construct it that the pad 14 can be swung outwardly into a position in which it forms, in effect, an extension of the members Ill, and I provide an abutment for limiting such outward swingin move ment of the pad. Conveniently, such abutment takes the form of a pin 26 extending between the two members 19 in position to engage the side of the pad 14 and limit its outward swinging movement. With the pad swung outwardly into engagement with the pin 26, it projects outwardly beyond the members 10 in a position such that its lower corner can engage and exert clamping effort against a narrow ledge or shoulder 25' on the object 25 which is to be held in position.

I claim as my invention:

A machine clamp, comprising a foot provided with two parallel spaced slots, similar clamp bars having corresponding ends received respectively in said slots, a pivot pin extending through said foot and clamp bars to provide a pivotal interconnection, a second pivot pin extendin be- "tween and interconnecting the opposite ends of "the clamp bars, a pressure pad pivotally mounted on said second pin between the clamp bars, said pressure pad having no portion greater in thickness than is the space between said bars whereby it can swing bodily into such space, an abut- :ment pin extending between said bars above said second pivot pin to engage said pressure pad and limit its outward swinging movement to a position in which it projects beyond the ends of the clamp bars and forms, in efiect, an extension thereof, said clamp bars being provided in their upper faces with series of aligned, spaced, transverse notches of arcuate shape, a cross member adapted for rotatable reception in any of the aligned notches of the clamp bars, and a clamp bolt extending through said cross member and through the space between the clamp bars.

WALTER W. CARROLL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 893,754 Russell July 21, 1908 1,490,063 Tower Apr. 8, 1924 1,676,289 Schmalz July 10, 1928 1,995,206 Geissbuhler Mar. 19, 1935 2,325,387 Fredrickson July 27, 1943 FOREIGN PATENTS Number Country Date 47,505 Sweden Sept. 24, 1919 111,382 Switzerland Sept. 16, 1925

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