Elongated-member-driving apparatus – With control means responsive to sensed condition – Work-responsive
Reexamination Certificate
1999-03-02
2001-04-17
Smith, Scott A. (Department: 3721)
Elongated-member-driving apparatus
With control means responsive to sensed condition
Work-responsive
C227S005000, C227S131000, C227S142000
Reexamination Certificate
active
06216935
ABSTRACT:
BACKGROUND AND FIELD OF THE INVENTION
The present invention is directed to a powerized stapler device and more particularly to a stapler device wherein the driving force imparted to the head of the stapler may be varied within a wide range such that a greater driving force is applied when a multiplicity of sheets are to be stapled and conversely, a lower driving force is applied where the staple is to be clinched through a limited number of sheets.
1. Prior Art
Powerized stapling devices have been available for many years, representative examples being disclosed in U.S. Pat. Nos. 2,403,947; 2,877,461; 2,957,174; 2,975,424; 3,016,538; 3,022,512; 3,026,518; 3,101,478; 3,151,329; 3,251,524, assigned to the assignee hereof. The references noted disclose, in general, staplers integrated into a housing, carrying an electromagnetic mechanism such as a solenoid, the armature of the solenoid being disposed above the drive head of the stapler. Insertion of articles to be stapled activates a switch mechanism energizing the solenoid and causing the armature to drive the stapler through an operating cycle
A difficulty inhering in staplers of the type described resides in the fact that the stapling force imparted is identical for stapling jobs consisting of a multiplicity of sheets and also for jobs involving only a few sheets. Where the applied force is sufficient for joining multiple sheets and the same force is utilized in joining jobs comprised of only a few sheets, one or the other of the jobs will be defective. More particularly, if the force is insufficient to drive a staple through a multiple sheet job, an effective clinching will not result. Conversely, if a force sufficient for multiple sheet stapling is utilized in connection with a two or three sheet job, the stapler will act in the manner of a punch, the base of the overdriven staple penetrating one or more of the sheets whereby the upper most ones of the sheets are not effectively connected to the remainder of the sheets.
A further problem inhering in the application of overly great stapling forces when connecting a limited number of sheets, resides in the excessive impact leaving an imprint surrounding the area of staple application.
A still further drawback of known powerized staplers, particularly when used to fasten a limited number of sheets, resides in the staple being applied with a rolling or angular clinch. The rolling clinch results from the fact that the sheets are moving a finite distance after the sensor, which activates the stapler, is energized. As a result, the legs of the staple penetrate the sheets while the sheets are still moving, whereby the base of the staple has passed a slight distance beyond the clinching anvil, resulting in a rolling or loosely applied staple. The described problem is of lesser significance where a multiplicity of sheets are to be stapled since the multiple sheets act as a support for the staple as it is driven. Additionally, the thickness of the multiple sheets assures that impact between the stapler head and the upper most sheet occurs promptly following energizing of the power mechanism since the upper most sheet of a thick stack will be closer to the stapler head than would be the case where only a few sheets are to be connected.
Various means have been proposed to provide stapling devices wherein the driving power may be adjusted. These known devices utilize electronic circuitry for varying the voltage applied to the solenoid or other electromagnetic driving means. While these devices enable the user to tailor the driving force, within a limited range, to the job at hand, they do not solve the problems discussed above, and particularly the problem of avoiding a rolling staple connection when used to join a limited number of sheets.
A further drawback of known powerized staplers resides in the fact that the power must be manually adjusted in accordance with the job at hand. Thus, where the user will sequentially staple thin and thick stacks of articles, adjustment must be manually effected between each application, greatly slowing the stapling procedure. Additionally, manual adjustment involves discretion on the part of the user and thus is a minimal aid to the occasional powerized stapler user.
SUMMARY OF THE INVENTION
The present invention may be summarized as directed to an improved powerized stapling device characterized in that a unique means is employed for varying the force of the stapling stroke, enabling a more precise and wider range of stapling force than is available to powerized staplers utilizing electronic adjustment of stapling force.
The invention is further directed to a variable power-stapling device, which automatically adjusts stapling force to the thickness of the articles to be stapled.
A still further object of the invention resides in the provision of a variable power stapler wherein adjustment of the stapling force functions, in addition, to vary the spacing between the stapler head and the upper most of the stack of sheets to be stapled. More particularly, adjustment of the stapling force to reduce the force also functions to shift the stapler drive head closer to the upper most sheet whereby the time lag between energization and actual driving of a staple is reduced. Conversely, where a large number of sheets are to be connected adjustment of the driving force to increase the same also results in moving the stapler head further from the upper most of the thick stack of articles maximizing inertia applied to the stapler.
The invention is further directed a unique means for varying the stapling force thereby eliminating the use of electronic controls. Known electronic controls, namely voltage reducers do not function below a threshold voltage eliminating the desired “soft touch” where a limited number of sheets or poly bags are to be stapled. More specifically, adjustment of stapling power in accordance with the invention is accomplished by providing an electromagnetic drive mechanism and particularly a solenoid which includes an armature incorporating a high permeability portion, adjustment of the stapling force being effected by shifting the position of the high permeability portion relative to the core of the solenoid. For example, where the major portion of the high permeability material is positioned such that it will be drawn into the solenoid upon energization, a greater force is applied to the armature than is the case is where a majority of the high permeability material is already located within the solenoid.
It is an object of the invention to provide a force adjustable stapling device wherein adjustment of the driving force is accompanied by a concomitant movement of the stapler head toward and away from the work.
A further object of the invention is the provision of a variable force stapling device, wherein the driving force is automatically varied responsive to the thickness of the stack of articles to be stapled.
A still further object of the invention is the provision of a means for varying the force applied in a stapling operation by varying the position of an armature with respect to an electromagnetic mechanism operatively coupled to the armature.
REFERENCES:
patent: 3345546 (1967-10-01), Beltramo
patent: 3346163 (1967-10-01), Manganaro
patent: 4524897 (1985-06-01), Bachmann
patent: 4592502 (1986-06-01), Judge
patent: 4611742 (1986-09-01), Rieker et al.
patent: 5161724 (1992-11-01), Radtke et al.
patent: 5354042 (1994-10-01), Coombs
patent: 5671879 (1997-09-01), Lin
Oussani Gregory P.
Oussani, Jr. James J.
Smith Scott A.
Sutton Paul J.
The Staplex Company, Inc.
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