Patent Application
20150217593
I. Field of the Invention
This invention relates generally to workmen's tools, and more particularly to a carpenter's square having separate arm members that can be rigidly joined to one another for use, but which can readily be separated for ease of storage in a tool box.
II. Background of the Art
There are numerous examples of carpenter's squares having separable or folding arms for ease of carrying, but for the most part, they suffer from a number of different drawbacks, not the least of which is the inability to quickly and rigidly join and separate the tool arms of the square without resort to additional tools. When it is recognized that one arm of a typical carpenter's square may be as long as 22½ inches and the other 16 inches, any play in the joint between the two arms can translate into a relatively large possible angular deviation from perpendicular at the end of the arm opposite the joint.
For example, U.S. Pat. No. 481,637 to Poole describes an arrangement where the arms of the square are undercut at their junction and screws are used to fasten the arms together. This arrangement requires a screwdriver to fasten the two arms together and unless the screws are tightened down snugly, there is an opportunity for play in the joint.
U.S. Pat. No. 556,840 to Biggs describes a carpenter's square in which one blade thereof has a terminal portion adapted to fit into a dove-tail groove formed in the other arm. Unless the tongue and groove arrangement is formed with very tight tolerances, the resulting play will result in a significant deviation of the opposite end of one arm from the perpendicular. Moreover, in use, wear in the tongue and groove joint will compound the problem.
U.S. Pat. No. 846,248 to Schmalz shows a tongue 3 which is inserted in a groove defined by arms 6 and 7 for interlocking. Screws 14 and 15 are then employed to more rigidly affix the halves of the square to one another.
U.S. Pat. No. 1,549,151 to Rasmussen discloses a square arrangement where the arms join along a diagonal, the two arms being undercut at the joint so that each arm is of half the thickness of the remaining portion of the arms in the location of the joint. A rack and pinion gear arrangement cooperating with a slide plate 11 is provided for holding the two parts together. A hook-like end on the slide plate fits into a slot formed in the adjacent arm and the slide plate bridges the joint. Again, a screwdriver must be used to rotate the pinion to first create a snug coupling and later used to release the two arms. Any play in the rack and pinion gear arrangement necessarily results in undue play between the mating arms of the square.
U.S. Pat. No. 5,819,427 (Rohweder) discloses a carpenter's square that can have the arms thereof separated for ease of storage and joined together during use includes a over-center latch arrangement designed to be no thicker than the thickness dimension of the arm members and which, when operated, tightly clamps the arms of the square at right angles to one another. A first arm of the square has an opening formed through the thickness dimension thereof along with alignment bores extending inwardly from a side edge thereof on either side of the opening. The second arm includes the over-center latch pivotally mounted in a slot or channel and includes a latch plate pivotally joined to a coupling member having a head thereon designed to fit within the opening on the first arm member. When the latch plate is manually actuated so as to reside within the slot of the second arm, the head on the coupling member cooperates with an edge defined by the opening in the first arm to tightly clamp the first and second arms one to the other. The present technology is a specific improvement over this technology.
Each reference cited within this document is incorporated by reference in its entirety.
One aspect of the present invention is to provide a separable carpenter's square having first and second arms that can be readily coupled and uncoupled without the use of any extra tools and which will provide a s joint between the two arms so as to prevent any play therebetween which can translate into inaccurate alignment of work pieces that are intended to meet at a right angle.
The separable carpenter's square in accordance with the present invention comprises a first elongated rectangular arm member having a pair of alignment bores formed in an edge surface thereof and an opening formed through a thickness dimension thereof intermediate the pair of alignment bores. A second elongated rectangular arm member has a pair of alignment protuberances that project outwardly from an edge surface thereof and which are adapted to be received in the alignment bores of the first arm member. The second arm member also has an elongated notch formed inwardly between the alignment protuberances. A latch means is pivotally mounted in the elongated notch in the second arm member and cooperates with the opening of the first arm member for releasably clamping the first and second arm members to one another. The latch means comprises an arcuate or tension-providing latch plate that is pivotally connected to the second arm member within the elongated notch. A coupling member is pivotally joined to the latch plate at one end thereof and has a head member affixed to the coupling member. The head member is adapted to fit within the opening formed in the first arm member such that rotation of the latch plate in a first direction forces the first and second arm members tightly together along the edge surface thereof carrying the alignment bores and alignment protuberances, respectively. By providing a snap engaging (e.g., posts or protuberances outward of the latch plate and receptor slots in the first arm member) connection between the coupling member and the head member, the tension providing latch plate provides a clamping force applied between the first arm member and the second arm member to ensure a snug fit. The snap engaging connection simplifies and speeds up secure and stable interconnection of the two arm members.
The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, wherein like numerals in the several views refer to corresponding parts.
As used in the following description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down” as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its access of elongation, or access of rotation, as appropriate.
Referring now to the drawings, this invention broadly provides an improved carpenter's square that can be separated into multiple components of generally equal size for ease of carrying in a toolbox and that can be readily rigidly joined to one another for use without any need to resort to the use of other tools to effect the coupling thereof.
Similar numbers in different figures identify similar elements.
With reference to the drawings, there is indicated generally by numeral 10, the carpenter's square comprising an embodiment of the present invention. It is seen to comprise first and second elongated, rigid, rectangular arm members 12 and 14 in
A first edge surface of arm member 12, i.e., the side edge 21, includes a pair of spaced-apart, generally circular alignment bores 18 and 20 formed inwardly thereof. Formed midway therebetween is a slot 22 that extends through the thickness dimension of the arm 12 and leads to an enlarged opening 24. The edges 26 and 28 of the opening are inwardly beveled to form a V-shaped groove therein.
The arm member 14 has an elongated notch or channel 30 centrally disposed and extending inwardly from an end edge 32 thereof. The notch 30 defines first and second parallel legs 34 and 36 and extending outwardly from the end edge 32 of these legs are alignment protuberances 38 and 40 which may comprise cylindrical pins in other shapes. The protuberances 38 and 40 are dimensioned to fit with a close tolerance within the alignment bores 18 and 20 formed inwardly of a side edge surface 21 of arm member 12.
With reference again to
The latch plate 46 has an offset segment 60 that cooperates with the stop 44 when it is hinged to the arm member 14 by means of the pins 48 and 50. The latch plate 46 further includes a longitudinal slot 62 formed through it along its midline. The slot is dimensioned to receive a first end of a coupling member 64 therein, the coupling member being pivotally secured in the slot 62 by means of a hinge pin 66 that passes through aligned bores 68, 70 and 72 when the coupling member 64 is inserted into the slot 62. A coil spring, as at 74, has a first end 76 thereof inserted into a recess 78 formed atop the coupling member 64 and with the other end 80 thereof engaging the top surface of the latch plate 46. The spring 74 serves to prevent the coupling member 64 from pivoting freely and biases the coupling member 64 against the stop 42.
The coupling member 64 includes a threaded stud 82 on which is threaded a head member 84. The bore in the head member into which the stud 82 is treaded preferably includes a plastic or rubber bushing (not shown) to resist inadvertent rotation of the head member on the stud. As best seen in the plan view of
The present invention and technology includes a separable carpenter's square shown in
(a) a first elongated rectangular arm member 12 having a pair of alignment bores 1820 formed in an edge surface 23 thereof and an opening 24 formed through a thickness dimension thereof intermediate the pair of alignment bores;
(b) a second elongated rectangular arm member 14 having a pair of alignment protuberances 3840 projecting outwardly from an edge surface thereof and adapted to be received in the alignment bores 1820 of the first arm member 12; and
(c) latch dual-plate 46a pivotally mounted in an elongated notch 53 of the second arm member and cooperating with the opening 24 of the first arm member 12 for releasably clamping the first 12 and second 14 arm members to one another;
wherein the latch dual-plate 46a and t64a comprises a) an arcuate, pivoting coupling member 64a having two longitudinal sides 79 and two posts 82a on the arcuate coupling member, one of the two posts 82a extending outwardly from each of the two longitudinal sides 79, pivoting within b) a latch plate 46a, and d) two receptor slots 27a 27b on opposed sides of an opening 24 in the first arm member, the latch plate 46a adapted to apply elongating strain on the arcuate, pivoting coupling member 64a when pressed down while the two posts 3840 are positioned within the two receptor slots 1820.
The separable carpenter's square has the latch plate 46a configured to elongate the arcuate, pivoting coupling member 64a by the elongating strain, when the latch plate 46a is moved downward into a closed position. The latch plate 46a is snapped by movement into position, releasably locking the two arm members 3840, the latch plate 46a and the coupling member 64a together. The separate carpenter's square slots 27a 27b in the opening 24 comprise a proximal concave surface to retain a post 84a.
The technology may be further described according to the Figures as a carpenter's square comprising:
(a) a first arm member 12 having first and second major rectangular surfaces with peripheral side and end edges of a predetermined thickness dimension extending between the first and second major surfaces,
(b) a second arm member 14 having first and second major rectangular surfaces with peripheral side and end edges of a thickness dimension equal to the predetermined thickness of the first arm member extending between the first and second major rectangular surfaces,
(c) an over-center latch assembly (comprising 46a and 64a) pivotally secured in the rectangular slot 53 in the second arm member 14, the latch assembly (comprising 46a and 64a) including,
With reference to
The latch plate 46a has an offset segment 60 that cooperates with the stop 44 when it is hinged to the arm member 14 by means of the pins 48 and 50. The latch plate 46 further includes a longitudinal slot 62a formed through it along its midline. The slot is dimensioned to receive a first end of a coupling member 64a therein, the coupling member being pivotally secured in the slot 62a by means of a hinge pin 66 that passes through aligned bores 68a, 70a and 72a when the coupling member 64a (shown in detail in
The novel coupling member 64a has eliminated (from
Operation
With the arm 12 separated from the arm 14 in
When the two arm members 12 and 14 are rigidly joined and held together by the clamping arrangement, all parts of the clamping arrangement lie between the upper and lower major surfaces of the arm members 12 and 14 so that the square will lay flush against a flat surface, allowing the carpenter to use the square for scribing lines on sheet material without rocking of the square.
As is illustrated in
Those skilled in the art can appreciate that the same coupling approach can be used in joining cooperating arms of a T-square by merely locating the opening 24 and the alignment bores 18 and 20 midway along the top arm of the T-square rather than at one end as shown in
This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
