Roger Bruce Ela, 84227 Paxton Rd, Spencer, MA 01562

4044894, Aug 30, 1977

May 25, 1976

5/689729

Donald C. McDonald - Sherborn MA
Roger B. Ela - Spencer MA
Francis E. Whittaker - Holliston MA

Walker Magnetics Group, Inc. - Worcester MA

B66C 104

214 1QD

Apparatus for the magnetically lifting and tilting an elongate load, e. g. , a steel beam, is disclosed. The apparatus comprises a plurality of electromagnets supported in a corresponding plurality of yokes in a linear array along a beam structure. On each yoke, a stepping motor is coupled to the respective electromagnet for controllably rotating the electromagnet around a pivotal axis which is parallel to the axis of the array. The motors are synchronously operated, thereby enabling an elongate load to be lifted by the electromagnets together and tilted around the pivotal axis. In a preferred construction, each end of each yoke is suspended on a plurality of tie elements connected to a vertically compliant spring suspension system mounted on the beam structure. The tie elements are arranged to minimize swinging or misalignment of the several electromagnetic lifting elements.

4370693, Jan 25, 1983

Jan 2, 1981

6/221990

Donald C. McDonald - Worcester MA
Roger B. Ela - Worcester MA
Dominic F. Pignataro - Worcester MA

H01F 1300

361145

In the electromagnet control apparatus described herein, demagnetization of the electromagnet and a workpiece held thereby, following a period of holding, is effected by stepwise adjustment of the phase setting of a power control means such as a triggerable, semi-conductor switching device, thereby controlling the average AC voltage applied to a full wave bridge through which the electromagnet is energized. Reversing switch means are interposed between the bridge and the electromagnet for reversing the direction of the energizing current at each successive step.

4633361, Dec 30, 1986

Oct 1, 1984

6/656312

Roger B. Ela - Spencer MA
Dominic F. Pignataro - Shrewsbury MA

Walker Magnetics Group, Inc. - Worcester MA

B25B 1100
H01F 1300

361145

An electromagnet control apparatus having a remote control switch assembly switchable between a number of positions representing full, variable, residual and zero levels of magnetization. Means are provided for causing the electromagnet to be fully energized for several seconds before being dropped to the residual level of magnetization whenever the switch assembly is switched to a residual setting.

4600964, Jul 15, 1986

Feb 25, 1985

6/705014

Roger B. Ela - Spencer MA
Paul H. Guerin - Clinton MA

Walker Magnetics Group, Inc. - Worcester MA

H01F 720

361144

In the lifting magnet system disclosed herein, demagnetization and releasing of a load are accomplished without switching inductively loaded d. c. power by employing a. c. energization, through respective bridge rectifiers, of entirely separate lifting and drop coils.